Institut für Geographie und Geologie
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Sonstige beteiligte Institutionen
- The Italian Federation of Parks and Nature Reserves (3)
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- Département de géographie, Université Abdou Moumouni Dioffo de Niamey, Niger (1)
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- Federazione Italiana Parchi e Riserve Naturali (Federparchi) (1)
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- Hochschule für angewandte Wissenschaften München, Fakultät für Tourismus (1)
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- Istituto di Salisburgo per la pianificazione regionale e le abitazioni (SIR) (1)
- Istituto di pianificazione urbana della Repubblica di Slovenia (UIRS) (1)
- La rete di aree protette alpine (ALPARC) (1)
- Lehrstuhl für Fernerkundung der Uni Würzburg, in Kooperation mit dem Deutschen Fernerkundungsdatenzentrum (DFD) des Deutschen Zentrums für Luft- und Raumfahrt (DLR) (1)
- Leuphana Universität Lüneburg (1)
- Salzburger Institut für Raumordnung und Wohnen (1)
- Sonderforschungsbereich Re-Figuration von Räumen (Technische Universität Berlin) (1)
- South African National Biodiversity Institute (SANBI) (1)
- Technische Universität Dresden (1)
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- 308377 (2)
- 20-3044-2-11 (1)
- 227159 (1)
- 243964 (1)
- 714087 (1)
- 776019 (1)
- 818182 (1)
- 834709 (1)
- LIFE12 BIO/AT/000143 (1)
- LIFE20 NAT/AT/000049 (1)
Background:
Schistosomiasis is a water-based disease that affects an estimated 250 million people, mainly in sub-Saharan Africa. The transmission of schistosomiasis is spatially and temporally restricted to freshwater bodies that contain schistosome cercariae released from specific snails that act as intermediate hosts. Our objective was to assess the contribution of remote sensing applications and to identify remaining challenges in its optimal application for schistosomiasis risk profiling in order to support public health authorities to better target control interventions.
Methods:
We reviewed the literature (i) to deepen our understanding of the ecology and the epidemiology of schistosomiasis, placing particular emphasis on remote sensing; and (ii) to fill an identified gap, namely interdisciplinary research that bridges different strands of scientific inquiry to enhance spatially explicit risk profiling. As a first step, we reviewed key factors that govern schistosomiasis risk. Secondly, we examined remote sensing data and variables that have been used for risk profiling of schistosomiasis. Thirdly, the linkage between the ecological consequence of environmental conditions and the respective measure of remote sensing data were synthesised.
Results:
We found that the potential of remote sensing data for spatial risk profiling of schistosomiasis is - in principle - far greater than explored thus far. Importantly though, the application of remote sensing data requires a tailored approach that must be optimised by selecting specific remote sensing variables, considering the appropriate scale of observation and modelling within ecozones. Interestingly, prior studies that linked prevalence of Schistosoma infection to remotely sensed data did not reflect that there is a spatial gap between the parasite and intermediate host snail habitats where disease transmission occurs, and the location (community or school) where prevalence measures are usually derived from.
Conclusions:
Our findings imply that the potential of remote sensing data for risk profiling of schistosomiasis and other neglected tropical diseases has yet to be fully exploited.
Sie sind wahrhaftig vernachlässigt, die Stadtteilzentren, Ladenzeilen, Ausfallstraßen; die Viertelzentren und Dorfkerne – eben all jene Geschäftslagen, die wir in unseren großen Städten irgendwo zwischen den Fußgängerbereichen der Cities und den Fachmarkagglomerationen entlang der Autobahnen finden. Nicht nur den Konsumenten, den Einzelhandelsunternehmen und der Stadtplanung fehlt es manchmal an Aufmerksamkeit für diese Geschäftslagen – nein, auch und vor allem der geographischen Handelsforschung: Man kann schwerlich übersehen, dass die Diskussion um den Konflikt zwischen „Innenstadt“ einerseits und „grüner Wiese“ andererseits, die seit mehr als zwanzig Jahren geführt wird, wenig Raum gelassen hat für eine wissenschaftliche Auseinandersetzung mit jenem Einzelhandel, der weder in der „Innenstadt“ noch auf der „grünen Wiese“ betrieben wird. Dieser Band versammelt deshalb zum ersten Mal Studien, die sich ausschließlich und engagiert mit den verschiedenen Typen vernachlässigter Geschäftslagen beschäftigen. Neben reichen empirischen Befunden aus Städten unterschiedlicher Größe (von Bonn bis Wien) findet der Leser in diesem Band theoretische und methodische Konzepte, die zur Erforschung der speziellen Probleme vernachlässigter Geschäftslagen geeignet sind. So entsteht eine wichtige Grundlage für den dringend notwendigen Ausbau dieser Forschungsrichtung und eine nützliche Arbeitshilfe für Stadtplaner und Standortgutachter.
Drei Dinge sind es, die den Erfolg eines Einzelhandelsbetriebes bestimmen: 1. Der Standort, 2. Der Standort und 3. Der Standort – dieses Bonmot kennt jeder, der beruflich mit dem Einzelhandel zu tun hat. Was aber einen guten Standort ausmacht, wie man ihn findet und ihn bei Kräften hält - das ist nicht so klar. Das Buch möchte hier ein wenig Licht ins Dunkel bringen und diskutiert deshalb in vier Beiträgen die theoretischen Grundlagen und praktischen Probleme von klassischen und modernen Methoden der Standortplanung, Standortbewertung und Einzugsbereichsmessung. Der Band richtig sich nicht nur an Standortplaner von Einzelhandelsunternehmen, die hier ein nützliches Kompendium für die tägliche Arbeit erhalten, sondern auch an Planer und Politiker, die über die Ansiedlung von Einzelhandels(-groß)betrieben zu entscheiden haben, und für die es oft von entscheidender Bedeutung ist zu wissen, wie ein neuer Standort in
bestehenden Strukturen eingreift.
Alle Autoren verfügen über langjährigen Erfahrung mit den im Buch behandelten Methoden – sowohl aus der Perspektive der akademischen Grundlangeforschung als auch aus der Perspektive der Auftragsforschung für Unternehmen und Kommunen. Dies bürgt für eine kenntnisreiche Verbindung von Wissenschaft und Praxis und macht das Buch auch für Studierende der Geographie und der Betriebswirtschaft interessant, die sich während des Studiums mit dem Einzelhandel beschäftigen oder eine berufliche Laufbahn in diesem Sektor anstreben.
Estimating flood risks and managing disasters combines knowledge in climatology, meteorology, hydrology, hydraulic engineering, statistics, planning and geography - thus a complex multi-faceted problem. This study focuses on the capabilities of multi-source remote sensing data to support decision-making before, during and after a flood event. With our focus on urbanized areas, sample methods and applications show multi-scale products from the hazard and vulnerability perspective of the risk framework. From the hazard side, we present capabilities with which to assess flood-prone areas before an expected disaster. Then we map the spatial impact during or after a flood and finally, we analyze damage grades after a flood disaster. From the vulnerability side, we monitor urbanization over time on an urban footprint level, classify urban structures on an individual building level, assess building stability and quantify probably affected people. The results show a large database for sustainable development and for developing mitigation strategies, ad-hoc coordination of relief measures and organizing rehabilitation.
West Africa is one of the fastest growing regions in the world with annual population growth rates of more than three percent for several countries. Since the 1950s, West Africa experienced a fivefold increase of inhabitants, from 71 to 353 million people in 2015 and it is expected that the region’s population will continue to grow to almost 800 million people by the year 2050. This strong trend has and will have serious consequences for food security since agricultural productivity is still on a comparatively low level in most countries of West Africa. In order to compensate for this low productivity, an expansion of agricultural areas is rapidly progressing. The mapping and monitoring of agricultural areas in West Africa is a difficult task even on the basis of remote sensing. The small scale extensive farming practices with a low level of agricultural inputs and mechanization make the delineation of cultivated land from other land cover and land use (LULC) types highly challenging. In addition, the frequent cloud coverage in the region considerably decreases the availability of earth observation datasets. For the accurate mapping of agricultural area in West Africa, high temporal as well as spatial resolution is necessary to delineate the small-sized fields and to obtain data from periods where different LULC types are distinguishable. However, such consistent time series are currently not available for West Africa. Thus, a spatio-temporal data fusion framework was developed in this thesis for the generation of high spatial and temporal resolution time series.
Data fusion algorithms such as the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) enjoyed increasing popularity during recent years but they have hardly been used for the application on larger scales. In order to make it applicable for this purpose and to increase the input data availability, especially in cloud-prone areas such as West Africa, the ESTARFM framework was developed in this thesis introducing several enhancements. An automatic filling of cloud gaps was included in the framework in order to use even partly cloud-covered Landsat images for the fusion without producing gaps on the output images. In addition, the ESTARFM algorithm was improved to automatically account for regional differences in the heterogeneity of the study region. Further improvements comprise the automation of the time series generation as well as the significant acceleration of the processing speed through parallelization. The performance of the developed ESTARFM framework was tested by fusing an 8-day NDVI time series from Landsat and MODIS data for a focus area of 98,000 km² in the border region between Burkina Faso and Ghana. The results of this test show the capability of the ESTARFM framework to accurately produce high temporal resolution time series while maintaining the spatial detail, even in such a heterogeneous and cloud-prone region.
The successfully tested framework was subsequently applied to generate consistent time series as the basis for the mapping of agricultural area in Burkina Faso for the years 2001, 2007, and 2014. In a first step, high temporal (8-day) and high spatial (30 m) resolution NDVI time series for the entire country and the three years were derived with the ESTARFM framework. More than 500 Landsat scenes and 3000 MODIS scenes were automatically processed for this purpose. From the fused ESTARFM NDVI time series, phenological metrics were extracted and together with the single time steps of NDVI served as input for the delineation of rainfed agricultural areas, irrigated agricultural areas and plantations. The classification was conducted with the random forest algorithm at a 30 m spatial resolution for entire Burkina Faso and the three years 2001, 2007, and 2014. For the training and validation of the classifier, a randomly sampled reference dataset was generated from Google Earth images based on expert knowledge of the region. The overall classification accuracies of 92% (2001), 91% (2007), and 91% (2014) indicate the well-functioning of the developed methodology. The resulting maps show an expansion of agricultural area of 91% from about 61,000 km² in 2001 to 116,900 km² in 2014. While rainfed agricultural areas account for the major part of this increase, irrigated areas and plantations also spread considerably. Especially the expansion of irrigation systems and plantation area can be explained by the promotion through various national and international development projects. The increase of agricultural areas goes in line with the rapid population growth in most of Burkina Faso’s provinces which still had available land resources for an expansion of agricultural area. An analysis of the development of agricultural areas in the vicinity of protected areas highlighted the increased human pressure on these reserves. The protection of the remnant habitats for flora and fauna while at the same time improving food security for a rapidly growing population, are the major challenges for the region in the future.
The developed ESTARFM framework showed great potential beyond its utilization for the mapping of agricultural area. Other large-scale research that requires a sufficiently high temporal and spatial resolution such as the monitoring of land degradation or the investigation of land surface phenology could greatly benefit from the application of this framework.
As a cradle of ancient Chinese civilization, the Yellow River Basin has a very long human-environment interrelationship, where early anthropogenic activities re- sulted in large scale landscape modifications. Today, the impact of this relationship
has intensified further as the basin plays a vital role for China’s continued economic
development. It is one of the most densely-populated, fastest growing, and most dynamic
regions of China with abundant natural and environmental resources providing a livelihood for almost 190 million people. Triggered by fundamental economic reforms, the
basin has witnessed a spectacular economic boom during the last decades and can be
considered as an exemplary blueprint region for contemporary dynamic Global Change
processes occurring throughout the country, which is currently transitioning from an
agrarian-dominated economy into a modern urbanized society. However, this resourcesdemanding growth has led to profound land use changes with adverse effects on the Yellow
River social-ecological systems, where complex challenges arise threatening a long-term
sustainable development.
Consistent and continuous remote sensing-based monitoring of recent and past land
cover and land use change is a fundamental requirement to mitigate the adverse impacts
of Global Change processes. Nowadays, technical advancement and the multitude of
available satellite sensors, in combination with the opening of data archives, allow the
creation of new research perspectives in regional land cover applications over heterogeneous landscapes at large spatial scales. Despite the urgent need to better understand the
prevailing dynamics and underlying factors influencing the current processes, detailed
regional specific land cover data and change information are surprisingly absent for this
region.
In view of the noted research gaps and contemporary developments, three major objectives are defined in this thesis. First (i), the current and most pressing social-ecological
challenges are elaborated and policy and management instruments towards more sustainability are discussed. Second (ii), this thesis provides new and improved insights on
the current land cover state and dynamics of the entire Yellow River Basin. Finally (iii),
the most dominant processes related to mining, agriculture, forest, and urban dynamics
are determined on finer spatial and temporal scales.
The complex and manifold problems and challenges that result from long-term abuse
of the water and land resources in the basin have been underpinned by policy choices,
cultural attitude, and institutions that have evolved over centuries in China. The tremendous economic growth that has been mainly achieved by extracting water and exploiting
land resources in a rigorous, but unsustainable manner, might not only offset the economic benefits, but could also foster social unrest. Since the early emergence of the first Chinese dynasties, flooding was considered historically as a primary issue in river management and major achievements have been made to tame the wild nature of the Yellow
River. Whereas flooding is therefore largely now under control, new environmental and
social problems have evolved, including soil and water pollution, ecological degradation,
biodiversity decline, and food security, all being further aggravated by anthropogenic
climate change. To resolve the contemporary and complex challenges, many individual
environmental laws and regulations have been enacted by various Chinese ministries.
However, these policies often pursue different, often contradictory goals, are too general
to tackle specific problems and are usually implemented by a strong top-down approach.
Recently, more flexible economic and market-based incentives (pricing, tradable permits,
investments) have been successfully adopted, which are specifically tailored to the respective needs, shifting now away from the pure command and regulating instruments.
One way towards a more holistic and integrated river basin management could be the
establishment of a common platform (e.g. a Geographical Information System) for data
handling and sharing, possibly operated by the Yellow River Basin Conservancy Commission (YRCC), where available spatial data, statistical information and in-situ measures
are coalesced, on which sustainable decision-making could be based. So far, the collected
data is hardly accessible, fragmented, inconsistent, or outdated.
The first step to address the absence and lack of consistent and spatially up-to-date
information for the entire basin capturing the heterogeneous landscape conditions was
taken up in this thesis. Land cover characteristics and dynamics were derived from
the last decade for the years 2003 and 2013, based on optical medium-resolution hightemporal MODIS Normalized Differenced Vegetation Index (NDVI) time series at 250 m.
To minimize the inherent influence of atmospheric and geometric interferences found in
raw high temporal data, the applied adaptive Savitzky-Golay filter successfully smoothed
the time series and substantially reduced noise. Based on the smoothed time series
data, a large variety of intra-annual phenology metrics as well as spectral and multispectral annual statistics were derived, which served as input variables for random
forest (RF) classifiers. High quality reference data sets were derived from very high
resolution imagery for each year independently of which 70 % trained the RF models. The
accuracy assessments for all regionally specific defined thematic classes were based on the
remaining 30 % reference data split and yielded overall accuracies of 87 % and 84 % for
2003 and 2013, respectively. The first regional adapted Yellow River Land Cover Products
(YRB LC) depict the detail spatial extent and distribution of the current land cover status
and dynamics. The novel products overall differentiate overall 18 land cover and use
classes, including classes of natural vegetation (terrestrial and aquatic), cultivated classes,
mosaic classes, non-vegetated, and artificial classes, which are not presented in previous
land cover studies so far.
Building on this, an extended multi-faceted land cover analysis on the most prominent
land cover change types at finer spatial and temporal scales provides a better and more
detailed picture of the Yellow River Basin dynamics. Precise spatio-temporal products
about mining, agriculture, forest, and urban areas were examined from long-trem Landsat
satellite time series monitored at annual scales to capture the rapid rate of change in four
selected focus regions. All archived Landsat images between 2000 and 2015 were used to
derive spatially continuous spectral-temporal, multi-spectral, and textural metrics. For
each thematic region and year RF models were built, trained and tested based on a stablepixels reference data set. The automated adaptive signature (AASG) algorithm identifies those pixels that did not change between the investigated time periods to generate a
mono-temporal reference stable-pixels data set to keep manual sampling requirements
to a minimum level. Derived results gained high accuracies ranging from 88 % to 98 %.
Throughout the basin, afforestation on the Central Loess Plateau and urban sprawl are
identified as most prominent drivers of land cover change, whereas agricultural land
remained stable, only showing local small-scale dynamics. Mining operations started in
2004 on the Qinghai-Tibet Plateau, which resulted in a substantial loss of pristine alpine
meadows and wetlands.
In this thesis, a novel and unique regional specific view of current and past land cover
characteristics in a complex and heterogeneous landscape was presented by using a
multi-source remote sensing approach. The delineated products hold great potential for
various model and management applications. They could serve as valuable components
for effective and sustainable land and water management to adapt and mitigate the
predicted consequences of Global Change processes.
Pedosedimentäre Archive liefern einen wichtigen Beitrag zur Rekonstruktion der Landschaftsgeschichte. Die anthropogene Besiedlung und Nutzung der Landoberfläche seit dem Beginn des Holozäns verursacht Boden-, Vegetations- und Reliefveränderungen, welche sich durch die Verbreitung von Böden mit ihren Erosionsstadien und Kolluvien zeigen. Das Ausmaß und die Art der Bodenerosion und die damit verbundene Bildung der Kolluvien werden neben den natürlichen Faktoren wesentlich durch die Landnutzung bestimmt. Böden und Kolluvien enthalten wichtige Informationen über die ursprüngliche Landschaft, ehemalige Landnutzungsphasen und Umweltveränderungen. Die spezifischen Merkmale in Kombination mit den archäologischen Befunden ermöglichen Rückschlüsse auf vergangene Natur- und Kulturräume.
Das Ziel der vorliegenden Arbeit ist es, ein besseres Verständnis über die Siedlungs- und Landschaftsentwicklung der untersuchten Gebiete in Franken zu erlangen. Hierfür ist es angebracht, mehrere räumlich verteilte Standorte zu untersuchen. Um den menschlichen Einfluss auf die prähistorische Landschaft besser verstehen zu können, kam ein interdisziplinärer Ansatz mit archäologischen und physisch-geographischen Methoden zur Anwendung. Die Umgebungen der einzelnen Untersuchungsstandorte wurden nach geomorphologischen Kriterien charakterisiert und ausgewählten Befunde nach bodenkundlichen Fragestellungen aufgenommen. Die Bestimmung der bodenphysikalischen und -chemischen Eigenschaften von Böden und Sedimenten erfolgte anhand repräsentativer Probenmengen. Bei ausgewählten Profilen kamen zusätzlich die Analysen zur Bestimmung der Gesamt- und Tonmineralogie sowie die Methode der 14C-Datierung für Bodensedimente, Tierknochen und Holzkohlen hinzu. Die physisch-geographischen Ergebnisse konnten anschließend mit den archäologischen Informationen ergänzt.
Die drei ausgewählten Untersuchungsgebiete befinden sich im Fränkischen Schichtstufenland. Der Bullenheimer Berg wurde aufgrund seiner bedeutenden Besiedlungsgeschichte ausgewählt. Die ausgewählten Profile liegen in verschiedenen Nutzungsarealen auf dem Plateau.
Die Standorte Marktbergel und Ergersheim liegen im Gebiet des Fränkischen Gipskarstes. Diese Untersuchungen sind ein Teil des DFG-geförderten Projektes „Prähistorische Mensch-Umwelt-Beziehungen im Gipskarst der Windsheimer Bucht, Nordbayern. Dolinen als Archive für Siedlungs- und Landschaftsentwicklung.“
Die vorliegenden Ergebnisse zeigen, dass der anthropogene Einfluss zu einer deutlichen Veränderung in der Landschaft führte. Für die Untersuchungsräume zeichnet sich eine lange Nutzungsgeschichte seit dem Beginn des Holozäns ab. Durch die Auswertung der Geländebefunde und der labortechnisch erzeugten Kennwerte konnten die untersuchten Profile in mehrere Phasen gegliedert werden. Es zeigten sich Stabilitätsphasen in denen Bodenbildung stattfinden konnte, aber auch geomorphodynamisch aktive Phasen der Erosion und Akkumulation von Bodensedimenten.
Urban areas are population, culture and infrastructure concentration points. Electricity blackouts or interruptions of water supply severely affect people when happening unexpected and at large scale. Interruptions of such infrastructure supply services alone have the potential to trigger crises. But when happening in concert with or as a secondary effect of an earthquake, for example, the crisis situation is often aggravated. This is the case for any country, but it has been observed that even highly industrialised
countries face severe risks when their degree of acquired dependency on services of what is termed Critical Infrastructure results in even bigger losses when occurring unexpectedly in a setting that usually has high reliability of services.
Zum Verständnis der komplexen Wechselwirkungen innerhalb des Klimasystems der Erde sind Kenntnisse über den hydrologischen Zyklus und den Energiekreislauf essentiell. Eine besondere Rolle obliegt hierbei der Evapotranspiration (ET), da sie eine wesentliche Teilkomponente beider oben erwähnter Kreisläufe ist. Die exakte Quantifizierung der regionalen, tatsächlichen Evapotranspiration innerhalb der Wasser- und Energiekreisläufe der Erdoberfläche auf unterschiedlichen zeitlichen und räumlichen Skalen ist für hydrologische, klimatologische und agronomische Fragestellungen von großer Bedeutung. Dabei ist eine realistische Abschätzung der regionalen tatsächlichen Evapotranspiration die wichtigste Herausforderung der hydrologischen Modellierung. Besonders die unterschiedlichen räumlichen und zeitlichen Auflösungen von Satelliteninformationen machen die Fernerkundung sowohl für globale als auch regionale hydrologischen Fragestellungen interessant. Zusätzlich zur Notwendigkeit des Prozessverständnisses des Wasserkreislaufs auf globaler Ebene kommt dessen regionale Bedeutung für die Landwirtschaft, insbesondere in Bewässerungssystemen arider Regionen. In ariden Klimazonen übersteigt die Menge der Verdunstung oft bei weitem die Niederschlagsmengen. Aufgrund der geringen Niederschlagsmenge muss in ariden agrarischen Regionen das zum Pflanzenwachstum benötigte Wasser mit Hilfe künstlicher Bewässerung aufgebracht werden. Der jeweilige lokale Bewässerungsbedarf hängt von der Feldfrucht und deren Wachstumsphase, den Klimabedingungen, den Bodeneigenschaften und der Ausdehnung der Wurzelzone ab. Die Evapotranspiration ist als Komponente der regionalen Wasserbilanz eine wichtige Steuerungsgröße und Effizienzindikator für das lokale Bewässerungsmanagement. Die Bewässe-rungslandwirtschaft verbraucht weltweit etwa 70 % der verfügbaren Süßwasservorkom-men. Dies wird als einer der Hauptgründe für die weltweit steigende Wasserknappheit identifiziert. Dabei liegt die Wasserentnahme des landwirtschaftlichen Sektors in den OECD Staaten im Mittel bei etwa 44 %, in den Staaten Mittelasiens bei über 90 %.
Bei der Erstellung der vorliegenden Arbeit kam die Methode der residualen Bestimmung der Energiebilanz zum Einsatz. Eines der weltweit am häufigsten eingesetzten und vali-dierten fernerkundlichen Residualmodelle zur ET Ableitung ist das SEBAL-Modell (Surface Energy Balance Algorithm for Land, mit über 40 veröffentlichten Studien. SEBAL eignet sich zur Quantifizierung der Verdunstung großflächiger Gebiete und wurde bisher über-wiegend in der Bewässerungslandwirtschaft eingesetzt. Aus diesen Gründen wurde es für die Bearbeitung der Fragestellungen in dieser Arbeit ausgewählt. SEBAL verwendet physikalische und empirische Beziehungen zur Berechnung der Energiebilanzkomponenten basierend auf Fernerkundungsdaten, bei gleichzeitig minimalem Einsatz bodengestützter Daten. Als Eingangsdaten werden u.a. Informationen über Strahlung, Bodenoberflächentemperatur, NDVI, LAI und Albedo verwendet. Zusätzlich zu SEBAL wurden einige Komponenten der SEBAL Weiterentwicklung METRIC (Mapping Evapotranspiration with Internalized Calibration) verwendet, um die Modellierung der ET vorzunehmen. METRIC überwindet einige Limitierungen des SEBAL Verfahrens und kann beispielsweise auch in stärker reliefierten Regionen angewendet werden. Außerdem ermöglicht die Integration einer gebietsspezifischen Referenz-ET sowie einer Landnutzungsklassifikation eine bessere regionale Anpassung des Residualverfahrens. Unter der Annahme der Bedingungen zum Zeitpunkt der Fernerkundungsaufnahme ergibt sich die Energiebilanz an der Erdoberfläche
RN = LvE + H + G. Demnach teilt sich die verfügbare Strahlungsenergie RN in die Komponenten latenter Wärme (LVE), fühlbarer Wärme (H) und Bodenwärme (G) auf. Durch Umstellen der Gleichung kann auf die latente Wärme geschlossen werden.
Das wesentliche Ziel der vorliegenden Arbeit ist die Optimierung, Erweiterung und Validierung des ausgewählten SEBAL Verfahrens zur regionalen Modellierung der Energiebilanzkomponenten und der daraus abgeleiteten tatsächlichen Evapotranspiration. Die validierten Modellergebnisse der Gebietsverdunstung der Jahre 2009-2011 sollen anschließend als Grundlage dienen, das Gesamtverständnis der regionalen Prozesse des Wasserkreislaufs zu verbessern. Die Arbeit basiert auf der Datengrundlage von MODIS Daten mit 1 km räumlicher Auflösung. Während die Komponenten verfügbare Strahlungsenergie und fühlbarer Wärmestrom physikalisch basiert ermittelt werden, beruht die Berechnung des Bodenwärmestroms ausschließlich auf empirischen Abschätzungen. Ein großer Nachteil des empirischen Ansatzes ist die Vernachlässigung des zeitlichen Versatzes zwischen Strahlungsbilanz und Bodenwärmestrom in Abhängigkeit der aktuellen Bodenfeuchtesituation.
Ein besonderer Schwerpunkt der vorliegenden Arbeit liegt auf der Bewertung und Verbesserung der Modellgüte des Bodenwärmestroms durch Verwendung eines neuen Ansatzes zur Integration von Bodenfeuchteinformationen. Daher wird in der Arbeit ein physikalischer Ansatz entwickelt der auf dem Ansatz der periodischen Temperaturveränderung basiert. Hierbei wurde neben dem ENVISAT ASAR SSM Produkt der TU Wien das operationelle Oberflächenbodenfeuchteprodukt ASCAT SSM als Fernerkundungseingangsdaten ausgewählt. Die mit SEBAL modellierten Energiebilanzkomponenten werden durch eine intensive Validierung mit bodengestützten Messungen bewertet, die Messungen stammen von Bodensensoren und Daten einer Eddy-Kovarianz-Station aus den Jahren 2009 bis 2011.
Die Region Khorezm gilt als charakteristisch für die wasserbezogene Problematik der Bewässerungslandwirtschaft Mittelasiens und wurde als Untersuchungsgebiet für diese Arbeit ausgewählt. Die wesentlichen Probleme dieser Region entstehen durch die nach wie vor nicht nachhaltige Land- und Wassernutzung, das marode Bewässerungsnetz mit einer Verlustrate von bis zu 40 % und der Bodenversalzung aufgrund hoher Grundwasserspiegel. Im Untersuchungsgebiet wurden in den Jahren 2010 und 2011 umfangreiche Feldarbeiten zur Erhebung lokaler bodengestützter Informationen durchgeführt.
Bei der Evaluierung der modellierten Einzelkomponenten ergab sich für die Strahlungsbi-lanz eine hohe Modellgüte (R² > 0,9; rRMSE < 0,2 und NSE > 0,5). Diese Komponente bildet die Grundlage bei der Bezifferung der für die Prozesse an der Erdoberfläche zur Verfügung stehenden Energie. Für die fühlbaren Wärmeströme wurden ebenfalls gute Ergebnisse erzielt, mit NSE von 0,31 und rRMSE von ca. 0,21. Für die residual bestimmte Größe der latenten Wärmeströmung konnte eine insgesamt gute Modellgüte festgestellt werden (R² > 0,6; rRMSE < 0,2 und NSE > 0,5). Dementsprechend gut wurde die tägliche Evapotranspiration modelliert. Hier ergab sich, nach der Interpolation täglicher Werte, eine insgesamt ausreichend gute Modellgüte (R² > 0,5; rRMSE < 0,2 und NSE > 0,4). Dies bestätigt die Ergebnisse vieler Energiebilanzstudien, die lediglich den für die Ableitung der Evapotranspiration maßgebenden Wärmestrom untersuchten. Die Modellergebnisse für den Bodenwärmestrom konnten durch die Entwicklung und Verwendung des neu entwickelten physikalischen Ansatzes von NSE < 0 und rRMSE von ca. 0,57 auf NSE von 0,19 und rRMSE von 0,35 verbessert werden. Dies führt zu einer insgesamt positiven Einschätzung des Verbesserungspotenzials des neu entwickelten Bodenwärmestromansatzes bei der Berechnung der Energiebilanz mit Hilfe von Fernerkundung.
Disentangling the relative effects of bushmeat availability on human nutrition in central Africa
(2015)
We studied links between human malnutrition and wild meat availability within the Rainforest Biotic Zone in central Africa. We distinguished two distinct hunted mammalian diversity distributions, one in the rainforest areas (Deep Rainforest Diversity, DRD) containing taxa of lower hunting sustainability, the other in the northern rainforest-savanna mosaic, with species of greater hunting potential (Marginal Rainforest Diversity, MRD). Wild meat availability, assessed by standing crop mammalian biomass, was greater in MRD than in DRD areas. Predicted bushmeat extraction was also higher in MRD areas. Despite this, stunting of children, a measure of human malnutrition, was greater in MRD areas. Structural equation modeling identified that, in MRD areas, mammal diversity fell away from urban areas, but proximity to these positively influenced higher stunting incidence. In DRD areas, remoteness and distance from dense human settlements and infrastructures explained lower stunting levels. Moreover, stunting was higher away from protected areas. Our results suggest that in MRD areas, forest wildlife rational use for better human nutrition is possible. By contrast, the relatively low human populations in DRD areas currently offer abundant opportunities for the continued protection of more vulnerable mammals and allow dietary needs of local populations to be met.
Der Einzelhandel in Ostmitteleuropa entwickelt sich seit dem Zusammenbruch des Sozialismus außerordentlich dynamisch. Er ist zugleich durch extreme Gegensätze gekennzeichnet: Das Spektrum der Betriebsformen reicht vom ambulanten Handel „aus der Hand“, der für viele Menschen existentielle Bedeutung einnimmt, bis zu Luxusgeschäften und SB-Warenhäusern westeuropäischer Ketten. Die Einzelhandelsstruktur wird so zum Spiegelbild der zunehmenden gesellschaftlichen Polarisierung in den Transformationsstaaten. Der Strukturwandel im Einzelhandel vollzieht sich dabei zwischen unternehmerischer Anpassung sowie administrativer Regulierung auf der lokalen Ebene und wachsender Internationalisierung. Dieses Spannungsfeld kann als maßgeblicher Erklärungsrahmen für die Transformation in Ostmitteleuropa gelten.
The Urban Heat Island (UHI) is the phenomenon of altered increased temperatures in urban areas compared to their rural surroundings. UHIs grow and intensify under extreme hot periods, such as during heat waves, which can affect human health and also increase the demand for energy for cooling. This study applies remote sensing and land use/land cover (LULC) data to assess the cooling effect of varying urban vegetation cover, especially during extreme warm periods, in the city of Munich, Germany. To compute the relationship between Land Surface Temperature (LST) and Land Use Land Cover (LULC), MODIS eight-day interval LST data for the months of June, July and August from 2002 to 2012 and the Corine Land Cover (CLC) database were used. Due to similarities in the behavior of surface temperature of different CLCs, some classes were reclassified and combined to form two major, rather simplified, homogenized classes: one of built-up area and one of urban vegetation. The homogenized map was merged with the MODIS eight-day interval LST data to compute the relationship between them. The results revealed that (i) the cooling effect accrued from urban vegetation tended to be non-linear; and (ii) a remarkable and stronger cooling effect in terms of LST was identified in regions where the proportion of vegetation cover was between seventy and almost eighty percent per square kilometer. The results also demonstrated that LST within urban vegetation was affected by the temperature of the surrounding built-up and that during the well-known European 2003 heat wave, suburb areas were cooler from the core of the urbanized region. This study concluded that the optimum green space for obtaining the lowest temperature is a non-linear trend. This could support urban planning strategies to facilitate appropriate applications to mitigate heat-stress in urban area.
BACKGROUND: Climate change will probably alter the spread and transmission intensity of malaria in Africa. OBJECTIVES: In this study, we assessed potential changes in the malaria transmission via an integrated weather disease model.
METHODS: We simulated mosquito biting rates using the Liverpool Malaria Model (LMM). The input data for the LMM were bias-corrected temperature and precipitation data from the regional model (REMO) on a 0.5 degrees latitude longitude grid. A Plasmodium falciparum infection model expands the LMM simulations to incorporate information on the infection rate among children. Malaria projections were carried out with this integrated weather disease model for 2001 to 2050 according to two climate scenarios that include the effect of anthropogenic land-use and land-cover changes on climate.
RESULTS: Model-based estimates for the present climate (1960 to 2000) are consistent with observed data for the spread of malaria in Africa. In the model domain, the regions where malaria is epidemic are located in the Sahel as well as in various highland territories. A decreased spread of malaria over most parts of tropical Africa is projected because of simulated increased surface temperatures and a significant reduction in annual rainfall. However, the likelihood of malaria epidemics is projected to increase in the southern part of the Sahel. In most of East Africa, the intensity of malaria transmission is expected to increase. Projections indicate that highland areas that were formerly unsuitable for malaria will become epidemic, whereas in the lower-altitude regions of the East African highlands, epidemic risk will decrease.
CONCLUSIONS: We project that climate changes driven by greenhouse-gas and land-use changes will significantly affect the spread of malaria in tropical Africa well before 2050. The geographic distribution of areas where malaria is epidemic might have to be significantly altered in the coming decades.
The focus of this analysis is on the early detection of forest health changes, specifically that of Norway spruce (Picea abies L. Karst.). In this analysis, we planned to examine the time (degree of early detection), spectral wavelengths and appropriate method for detecting vitality changes. To accomplish this, a ring-barking experiment with seven subsequent laboratory needle measurements was carried out in 2013 and 2014 in an area in southeastern Germany near Altötting. The experiment was also accompanied by visual crown condition assessment. In total, 140 spruce trees in groups of five were ring-barked with the same number of control trees in groups of five that were selected as reference trees in order to compare their development. The laboratory measurements were analysed regarding the separability of ring-barked and control samples using spectral reflectance, vegetation indices and derivative analysis. Subsequently, a random forest classifier for determining important spectral wavelength regions was applied. Results from the methods are consistent and showed a high importance of the visible (VIS) spectral region, very low importance of the near-infrared (NIR) and minor importance of the shortwave infrared (SWIR) spectral region. Using spectral reflectance data as well as indices, the earliest separation time was found to be 292 days after ring-barking. The derivative analysis showed that a significant separation was observed 152 days after ring-barking for six spectral features spread through VIS and SWIR. A significant separation was detected using a random forest classifier 292 days after ring-barking with 58% separability. The visual crown condition assessment was analysed regarding obvious changes of vitality and the first indication was observed 302 days after ring-barking as bark beetle infestation and yellowing of foliage in the ring-barked trees only. This experiment shows that an early detection, compared with visual crown assessment, is possible using the proposed methods for this specific data set. This study will contribute to ongoing research for early detection of vitality changes that will support foresters and decision makers.
In this study, polarimetric Synthetic Aperture Radar (PolSAR) data at X-, C- and L-Bands, acquired by the satellites: TerraSAR-X (2011), Radarsat-2 (2011), ALOS (2010) and ALOS-2 (2016), were used to characterize the tundra land cover of a test site located close to the town of Tuktoyaktuk, NWT, Canada. Using available in situ ground data collected in 2010 and 2012, we investigate PolSAR scattering characteristics of common tundra land cover classes at X-, C- and L-Bands. Several decomposition features of quad-, co-, and cross-polarized data were compared, the correlation between them was investigated, and the class separability offered by their different feature spaces was analyzed. Certain PolSAR features at each wavelength were sensitive to the land cover and exhibited distinct scattering characteristics. Use of shorter wavelength imagery (X and C) was beneficial for the characterization of wetland and tundra vegetation, while L-Band data highlighted differences of the bare ground classes better. The Kennaugh Matrix decomposition applied in this study provided a unified framework to store, process, and analyze all data consistently, and the matrix offered a favorable feature space for class separation. Of all elements of the quad-polarized Kennaugh Matrix, the intensity based elements K0, K1, K2, K3 and K4 were found to be most valuable for class discrimination. These elements contributed to better class separation as indicated by an increase of the separability metrics squared Jefferys Matusita Distance and Transformed Divergence. The increase in separability was up to 57% for Radarsat-2 and up to 18% for ALOS-2 data.
Interactions between different formative processes are reflected in the internal structure of rock glaciers. Therefore, the detection of subsurface conditions can help to enhance our understanding of landform development. For an assessment of subsurface conditions, we present an analysis of the spatial variability of active layer thickness, ground ice content and frost table topography for two different rock glaciers in the Eastern Swiss Alps by means of quasi-3-D electrical resistivity imaging (ERI). This approach enables an extensive mapping of subsurface structures and a spatial overlay between site-specific surface and subsurface characteristics. At Nair rock glacier, we discovered a gradual descent of the frost table in a downslope direction and a constant decrease of ice content which follows the observed surface topography. This is attributed to ice formation by refreezing meltwater from an embedded snow bank or from a subsurface ice patch which reshapes the permafrost layer. The heterogeneous ground ice distribution at Uertsch rock glacier indicates that multiple processes on different time domains were involved in the development. Resistivity values which represent frozen conditions vary within a wide range and indicate a successive formation which includes several advances, past glacial overrides and creep processes on the rock glacier surface. In combination with the observed topography, quasi-3-D ERI enables us to delimit areas of extensive and compressive flow in close proximity. Excellent data quality was provided by a good coupling of electrodes to the ground in the pebbly material of the investigated rock glaciers. Results show the value of the quasi-3-D ERI approach but advise the application of complementary geophysical methods for interpreting the results.
Der anthropogene Klimawandel ist eine der größten Herausforderungen des 21. Jahrhunderts. Eine Hauptschwierigkeit liegt dabei in der Unsicherheit bezüglich der regionalen Änderung von Niederschlag und Temperatur. Hierdurch wird die Entwicklung geeigneter Anpassungsstrategien deutlich erschwert.
In der vorliegenden Arbeit werden vier Evaluationsansätze mit insgesamt 13 Metriken für aktuelle globale (zwei Generationen) und regionale Klimamodelle entwickelt und verglichen, um anschließend eine Analyse der Projektionsunsicherheit vorzunehmen. Basierend auf den erstellten Modellbewertungen werden durch Gewichtung Aussagen über den Unsicherheitsbereich des zukünftigen Klimas getroffen. Die Evaluation der Modelle wird im Mittelmeerraum sowie in acht Unterregionen durchgeführt. Dabei wird der saisonale Trend von Temperatur und Niederschlag im Evaluationszeitraum 1960–2009 ausgewertet. Zusätzlich wird für bestimmte Metriken jeweils das klimatologische Mittel oder die harmonischen Zeitreiheneigenschaften evaluiert. Abschließend werden zum Test der Übertragbarkeit der Ergebnisse neben den Hauptuntersuchungsgebieten sechs global verteilte Regionen untersucht. Außerdem wird die zeitliche Konsistenz durch Analyse eines zweiten, leicht versetzten Evaluationszeitraums behandelt, sowie die Abhängigkeit der Modellbewertungen von verschiedenen Referenzdaten mit Hilfe von insgesamt drei Referenzdatensätzen untersucht.
Die Ergebnisse legen nahe, dass nahezu alle Metriken zur Modellevaluierung geeignet sind. Die Auswertung unterschiedlicher Variablen und Regionen erzeugt Modellbewertungen, die sich in den Kontext aktueller Forschungsergebnisse einfügen. So wurde die Leistung der globalen Klimamodelle der neusten Generation (2013) im Vergleich zur Vorgängergeneration (2007) im Schnitt ähnlich hoch bzw. in vielen Situationen auch stärker eingeordnet. Ein durchweg bestes Modell konnte nicht festgestellt werden. Der Großteil der entwickelten Metriken zeigt für ähnliche Situationen übereinstimmende Modellbewertungen. Bei der Gewichtung hat sich der Niederschlag als besonders geeignet herausgestellt. Grund hierfür sind die im Schnitt deutlichen Unterschiede der Modellleistungen in Zusammenhang mit einer geringeren Simulationsgüte. Umgekehrt zeigen die Metriken für die Modelle der Temperatur allgemein überwiegend hohe Evaluationsergebnisse, wodurch nur wenig Informationsgewinn durch Gewichtung erreicht werden kann. Während die Metriken gut für unterschiedliche Regionen und Skalenniveaus verwendet werden Evaluationszeiträume nicht grundsätzlich gegeben. Zusätzlich zeigen die Modellranglisten unterschiedlicher Regionen und Jahreszeiten häufig nur geringe Korrelationen. Dies gilt besonders für den Niederschlag. Bei der Temperatur sind hingegen leichte Übereinstimmungen auszumachen. Beim Vergleich der mittleren Ranglisten über alle Modellbewertungen und Situationen der Hauptregionen des Mittelmeerraums mit den Globalregionen besteht eine signifikante Korrelation von 0,39 für Temperatur, während sie für Niederschlag um null liegt. Dieses Ergebnis ist für alle drei verwendeten Referenzdatensätze im Mittelmeerraum gültig. So schwankt die Korrelation der Modellbewertungen des Niederschlags für unterschiedliche Referenzdatensätze immer um Null und die der Temperaturranglisten zwischen 0,36 und 0,44. Generell werden die Metriken als geeignete Evaluationswerkzeuge für Klimamodelle eingestuft. Daher können sie einen Beitrag zur Änderung des Unsicherheitsbereichs und damit zur Stärkung des Vertrauens in Klimaprojektionen leisten.
Die Abhängigkeit der Modellbewertungen von Region und Untersuchungszeitraum muss dabei jedoch berücksichtigt werden. So besitzt die Analyse der Konsistenz von Modellbewertungen sowie der Stärken und Schwächen der Klimamodelle großes Potential für folgende Studien, um das Vertrauen in Modellprojektionen weiter zu steigern.
Eine lange Tradition im japanischen Einzelhandel besitzen die oftmals schmalen und überdachten Einkaufspassagen (Shoutengai). Charakteristisch ist die Aneinanderreihung von kleinflächigen, unabhängigen und oftmals familiengeführten Fachgeschäften. Diese sind sowohl im Einzelhandel, Dienstleistungsgewerbe als auch in der Gastronomie angesiedelt und dienen nicht nur als zentrales Versorgungszentrum in Fußnähe, sondern sind auch Kommunikationsmittelpunkt einer Nachbarschaft oder eines Stadtbezirks. Das Ziel der Arbeit ist die Darstellung der momentanen Situation traditioneller Einkaufspassagen in Japan und welchen Herausforderungen diese aktuell und zukünftig gegenüberstehen. Mangelnde Kundennachfrage, erhöhte Konkurrenzsituation, steigende Steuerabgaben oder fehlende Nachfolger stehen beispielhaft für die Probleme, mit denen sich viele Inhaber konfrontiert sehen. Durch die empirische Untersuchung sollen Determinanten des Erfolgs bzw. Misserfolgs erarbeitet werden. Hierbei wurden von Juni 2015 bis Juli 2016 in Kyoto und Osaka 21 Einkaufspassagen mit insgesamt 3.469 Geschäftsflächen kartiert, von denen wiederum acht Einkaufspassagen näher untersucht wurden. Dabei haben 513 Betriebe an einer standardisierten Befragung teilgenommen und es wurden mehrere Leitfadeninterviews mit Shoutengai-Vereinen sowie Stadtverwaltungen und Wirtschaftsförderern geführt. Als theoretische Grundlagen der vorliegenden Arbeit dient insbesondere die Akteurs- und Handlungstheorie und wie die Aktivitäten der Geschäftsbetreiber die Passagen positiv bzw. negativ beeinflussen. Flankierenden Charakter besitzen zudem die Institutionentheorie, anhand derer der Einfluss politischer Entscheidungen erörtert wird sowie zyklische Theorieansätze, um eine Einordnung der traditionellen Einkaufspassagen in Japans Einzelhandelslandschaft durchzuführen.
Seit über drei Jahrzehnten sinkt landesweit die Zahl der Einzelhändler, die Gründe für den Niedergang sind vielfältig. Insbesondere Einzelgeschäfte mit einer niedrigen einstelligen Zahl an Mitarbeitern waren und sind auch weiterhin im Rückgang inbegriffen. Über ein Drittel der befragten Geschäftsinhaber planen in den nächsten fünf Jahren die Geschäftsführung aufzugeben, zwei Drittel von ihnen haben keinen Nachfolger für ihr Geschäft. Zunehmende Schließungen tragen zu Trading-Down Prozessen der gesamten Passage bei. Hohe Leerstandsquoten von bis zu über 50 %, verbunden mit ungepflegten Gebäudefassaden, einem schlechten Beleuchtungskonzept und begrenzter Produktauswahl führen zu einer unattraktiven Einkaufsatmosphäre, resultierend in einem Kundenmangel. Die Diversifizierung der Betriebsformen ab den 1960er Jahren und Deregulierungsprozesse der Binnenhandelspolitik beförderten die Konkurrenzsituation der Einkaufspassagen und bildeten die Grundlage dieser Abwärtsentwicklung.
Einige Immobiliengesellschaften nutzen dies für ihre Zwecke und erwerben einige Ladenzeilen, um diese großflächigen zu Wohnhäusern umzubauen. Die Einkaufspassagen erfahren dadurch einen Funktionswandel und verlieren zunehmend ihren ursprünglichen Charakter. Die Ergebnisse tragen dazu bei, die aktuelle Einzelhandelslandschaft Japans zu erfassen und stadtplanerischen Instrumenten bei der künftigen Planung zu unterstützen.
Home on the Range: Factors Explaining Partial Migration of African Buffalo in a Tropical Environment
(2012)
Partial migration (when only some individuals in a population undertake seasonal migrations) is common in many species and geographical contexts. Despite the development of modern statistical methods for analyzing partial migration, there have been no studies on what influences partial migration in tropical environments. We present research on factors affecting partial migration in African buffalo (Syncerus caffer) in northeastern Namibia. Our dataset is derived from 32 satellite tracking collars, spans 4 years and contains over 35,000 locations. We used remotely sensed data to quantify various factors that buffalo experience in the dry season when making decisions on whether and how far to migrate, including potential man-made and natural barriers, as well as spatial and temporal heterogeneity in environmental conditions. Using an information-theoretic, non-linear regression approach, our analyses showed that buffalo in this area can be divided into 4 migratory classes: migrants, non-migrants, dispersers, and a new class that we call "expanders". Multimodel inference from least-squares regressions of wet season movements showed that environmental conditions (rainfall, fires, woodland cover, vegetation biomass), distance to the nearest barrier (river, fence, cultivated area) and social factors (age, size of herd at capture) were all important in explaining variation in migratory behaviour. The relative contributions of these variables to partial migration have not previously been assessed for ungulates in the tropics. Understanding the factors driving migratory decisions of wildlife will lead to better-informed conservation and land-use decisions in this area.
The contact of hot melt with liquid water - called Molten Fuel Coolant Interaction (MFCI) - can result in vivid explosions. Such explosions can occur in different scenarios: in steel or powerplants but also in volcanoes. Because of the possible dramatic consequences of such explosions an investigation of the explosion process is necessary.
Fundamental basics of this process are already discovered and explained, such as the frame conditions for these explosions. It has been shown that energy transfer during an MFCI-process can be very high because of the transfer of thermal energy caused by positive feedback mechanisms.
Up to now the influence of several varying parameters on the energy transfer and the explosions is not yet investigated sufficiently. An important parameter is the melt temperature, because the amount of possibly transferable energy depends on it. The investigation of this influence is the main aim of this work. Therefor metallic tin melt was used, because of its nearly constant thermal material properties in a wide temperature range. With tin melt research in the temperature range from 400 °C up to 1000 °C are
possible.
One important result is the lower temperature limit for vapor film stability in the experiments. For low melt temperatures up to about 600 °C the vapor film is so unstable that it already can collapse before the mechanical trigger. As expected the transferred thermal energy all in all increases with higher temperatures. Although this effect sometimes is superposed by other influences such as the premix of melt and water, the result is confirmed after a consequent filtering of the remaining influences. This trend is not only recognizable in the amount of transferred energy, but also in the fragmentation of melt or the vaporizing water. But also the other influences on MFCI-explosions showed interesting results in the frame of this work. To perform the experiments the installation and preparation of the experimental Setup in the laboratory were necessary.
In order to compare the results to volcanism and to get a better investigation of the brittle fragmentation
of melt additional runs with magmatic melt were made. In the results the thermal power during energy transfer could be estimated. Furthermore the model of “cooling fragments “ could be usefully applied.
In the 1960s, when most African nations gained their independence after the age of colonialism, several theories and strategies emerged with the goal of "developing" these apparently "underdeveloped" territories. One of the most influential approaches for this task was represented in Julius K. Nyerere´s idea of Ujamaa, the Tanzanian version of African socialism.
Even before the Arusha Declaration established Ujamaa as a national development strategy in 1967, several groups of politicized young farmers took to the empty countryside of Tanzania to implement their own version of cooperative development. From one of these attempts emerged the Ruvuma Development Association (RDA), which organized up to 18 villages in southwestern Tanzania. The RDA became the inspiration for Nyerere´s concretization of Ujamaa and its implementation on national level. Yet, the central state could not replicate the success of the peasants, which was based on voluntariness and intrinsic motivation.
In 2015, this exploratory study has revisited the Region of Ruvuma. Through a case study approach, relying mostly on qualitative methods, new insights into the local history of Ujamaa and its perception have been gathered. In particular, narrative interviews with contemporary witnesses and group interviews with the present-day farmers’ groups have been conducted. Furthermore, NGOs active within the region, as well as regional and local government institutions were among the key stakeholders identified to concretize the local narrative of Ujamaa development. All interviews were analyzed according to the principles of qualitative content analysis. Additionally, individual villager questionnaires were used to achieve a more holistic picture of the local perception of development, challenges and the Ujamaa era.
None of the original Ujamaa groups of the times of the RDA was still operational at the time of research and no case of village-wide organization of collective agriculture could be observed. Nevertheless, in all of the three case study villages, several farmers’ groups (vikundi) were active in organizing development activities for their members. Furthermore, the perception of the Ujamaa era was generally positive throughout all of the case study sites. Yet, there have been significant differences in this perception, based on the village, age, gender and field size of the recipients. Overall, the period of Ujamaa was seen as an inspiration for present-day group activities, and the idea of such activities as a remedy for the developmental challenges of these villages was common among all stakeholders.
This thesis concludes that the positive perception of group activities as a vehicle for village development and the perception of Ujamaa history as a positive asset for the inception and organization of farmers’ groups would be highly beneficial to further attempts to support such development activities. However, the limitations in market access and capital availability for these highly-motivated group members have to be addressed by public and private development institutions. Otherwise, "the smell of Ujamaa" will be of little use for the progress of these villages.
The Kaapvaal Craton hosts a number of large gold deposits (e.g. Witwatersrand Supergroup) which mining companies have exploited at certain stratigraphic positions. It also hosts the largest platinum group element (PGE) deposits (e.g. Bushveld Igneous Complex) which mining companies have exploited in different mineralised layered magmatic zones. In spite of the extensive exploration history in the Kaapvaal Craton, the origin of the Witwatersrand gold deposits and Bushveld Igneous Complex PGE deposits has remained one of the most debated topics in economic geology. The goal of this study was to identify the geochemical characteristics of marine shales in the Barberton, Witwatersrand, and Transvaal supergroups in South Africa in order to make inferences on their sediment provenance and siderophile element endowments. Understanding why some of the Archaean and Proterozoic hinterlands are heavily mineralised, compared to others with similar geological characteristics, will aid in the development of more efficient exploration models. Fresh, unmineralised marine shales from the Barberton (Fig Tree and Moodies groups), Witwatersrand (West Rand and Central Rand groups), and Transvaal (Black Reef Formation and Pretoria Group) supergroups were sampled from drill core and underground mining exposures. Analytical methods, such as X-ray powder diffraction (XRD), optical microscopy, X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and electron microprobe analysis (EMPA) were applied to comprehensively characterise the shales. All of the Au and PGE assays examined the newly collected shale samples.
The Barberton Supergroup shales consist mainly of quartz, illite, chlorite, and albite, with diverse heavy minerals, including sulfides and oxides, representing the minor constituents. The regionally persistent Witwatersrand Supergroup shales consist mainly of quartz, muscovite, and chlorite, and also contain minor constituents of sulfides and oxides. The Transvaal Supergroup shales comprise quartz, chlorite, and carbonaceous material. Major, trace (including rare-earth element) concentrations were determined for shales from the above supergroups to constrain their source and post-depositional evolution. Chemical variations were observed in all the studied marine shales. Results obtained from this study revealed that post-depositional modification of shale chemistry was significant only near contacts with over- and underlying coarser-grained siliciclastic rocks and along cross-cutting faults, veins, and dykes. Away from such zones, the shale composition remained largely unaltered and can be used to draw inferences concerning sediment provenance and palaeoweathering in the source region and/or on intrabasinal erosion surfaces. Evaluation of weathering profiles through sections of the studied supergroups revealed that the shales therein are characterised by high chemical index of alteration (CIA), chemical index of weathering (CIW), and index of compositional variability (ICV), suggesting that the source area was lithologically complex and subject to intense chemical weathering.
A progressive change in the chemical composition was identified, from a dominant ultramafic–mafic source for the Fig Tree Group to a progressively felsic–plutonic provenance for the Moodies Group. The West Rand Group of the Witwatersrand Supergroup shows a dominance of tonalite–trondhjemite–granodiorite and calcalkaline granite sources. Compositional profiles through the only major marine shale unit within the Central Rand Group indicate the progressive unroofing of a granitic source in an otherwise greenstone-dominated hinterland during the course of sedimentation. No plausible likely tectonic setting was obtained through geochemical modelling. However, the combination of the systematic shale chemistry, geochronology, and sedimentology in the Witwatersrand Supergroup supports the hypothesised passive margin setting for the >2.98 to 2.91 Ga West Rand Group, and an active continental margin source for the overlying >2.90 to 2.78 Ga Central Rand Group, along with a foreland basin setting for the latter.
Ultra-low detection limit analyses of gold and PGE concentrations revealed a variable degree of gold accumulation within pristine unmineralised shales. All the studied shales contain elevated gold and PGE contents relative to the upper continental crust, with marine shales from the Central Rand Group showing the highest Au (±9.85 ppb) enrichment. Based on this variation in the provenance of contemporaneous sediments in different parts of the Kaapvaal Craton, one can infer that the siderophile elements were sourced from a fertile hinterland, but concentrated into the marine shales by a combination of different processes. It is proposed that accumulation of siderophile elements in the studied marine shales was mainly controlled by mechanical coagulation and aggregation. These processes involved suspended sediments, fine gold particles, and other trace elements being trapped in marine environments. Mechanical coagulation and aggregation resulted in gold enrichments by 2–3 orders of magnitude, whereas some of the gold in these marine shales can be reconciled by seawater adsorption into sedimentary pyrite.
For the source of gold and PGEs in the studied marine shales in the Kaapvaal Craton, a genetic model is proposed that involves the following:
(1) A highly siderophile elements enriched upper mantle domain, herein referred to as “geochemically anomalous mantle domain”, from which the Kaapvaal crust was sourced. This mantle domain enriched in highly siderophile elements was formed either by inhomogeneous mixing with cosmic material that was added during intense meteorite bombardment of the Hadaean to Palaeoarchaean Earth or by plume-like ascent of relics from the core–mantle boundary. In both cases, elevated siderophile elements concentrations would be expected. The geochemically anomalous mantle domain is likely the ultimate source of the Witwatersrand modified palaeoplacer gold deposits and was tapped again ca. 2.054 Ga during the emplacement of the Bushveld Igneous Complex. Therefore, I propose that there is a genetic link (i.e. common geochemically anomalous mantle source) between the Witwatersrand gold deposits and the younger Bushveld Igneous Complex PGE deposits.
(2) Scavenging of crustal gold by various surface processes such as trapping of gold from Archaean/Palaeoproterozoic river water on the surface of local photosynthesizing cyanobacterial or microbial mats, and reworking of these mats into erosion channels during flooding events.
The above two models complement each other, with model (1) providing a common geological source for the Witwatersrand gold and Bushveld Igneous Complex PGE deposits, and model (2) explaining the processes responsible for Witwatersrand-type gold pre-concentration processes. In sequences such as the Transvaal Supergroup, a less fertile hinterland and/or less reworking of older sediments led to a correspondingly lower gold endowment. These findings indicate temporal distribution of siderophile elements in the upper crust (e.g. marine shales). The overall implications of these findings are that background concentrations of gold and PGEs can be used to target potential exploration areas in other cratons of similar age. This increases the likelihood of finding other Witwatersrand-type gold or Bushveld Igneous Complex-type PGE deposits in other cratons.
Robust risk assessment requires accurate flood intensity area mapping to allow for the identification of populations and elements at risk. However, available flood maps in West Africa lack spatial variability while global datasets have resolutions too coarse to be relevant for local scale risk assessment. Consequently, local disaster managers are forced to use traditional methods such as watermarks on buildings and media reports to identify flood hazard areas. In this study, remote sensing and Geographic Information System (GIS) techniques were combined with hydrological and statistical models to delineate the spatial limits of flood hazard zones in selected communities in Ghana, Burkina Faso and Benin. The approach involves estimating peak runoff concentrations at different elevations and then applying statistical methods to develop a Flood Hazard Index (FHI). Results show that about half of the study areas fall into high intensity flood zones. Empirical validation using statistical confusion matrix and the principles of Participatory GIS show that flood hazard areas could be mapped at an accuracy ranging from 77% to 81%. This was supported with local expert knowledge which accurately classified 79% of communities deemed to be highly susceptible to flood hazard. The results will assist disaster managers to reduce the risk to flood disasters at the community level where risk outcomes are first materialized.
River deltas belong to the most densely settled places on earth. Although they only account for 5% of the global land surface, over 550 million people live in deltas. These preferred livelihood locations, which feature flat terrain, fertile alluvial soils, access to fluvial and marine resources, a rich wetland biodiversity and other advantages are, however, threatened by numerous internal and external processes. Socio-economic development, urbanization, climate change induced sea level rise, as well as flood pulse changes due to upstream water diversion all lead to changes in these highly dynamic systems. A thorough understanding of a river delta's general setting and intra-annual as well as long-term dynamic is therefore crucial for an informed management of natural resources. Here, remote sensing can play a key role in analyzing and monitoring these vast areas at a global scale. The goal of this study is to demonstrate the potential of intra-annual time series analyses at dense temporal, but coarse spatial resolution for inundation characterization in five river deltas located in four different countries. Based on 250 m MODIS reflectance data we analyze inundation dynamics in four densely populated Asian river deltas-namely the Yellow River Delta (China), the Mekong Delta (Vietnam), the Irrawaddy Delta (Myanmar), and the Ganges-Brahmaputra (Bangladesh, India)-as well as one very contrasting delta: the nearly uninhabited polar Mackenzie Delta Region in northwestern Canada for the complete time span of one year (2013). A complex processing chain of water surface derivation on a daily basis allows the generation of intra-annual time series, which indicate inundation duration in each of the deltas. Our analyses depict distinct inundation patterns within each of the deltas, which can be attributed to processes such as overland flooding, irrigation agriculture, aquaculture, or snowmelt and thermokarst processes. Clear differences between mid-latitude, subtropical, and polar deltas are illustrated, and the advantages and limitations of the approach for inundation derivation are discussed.
Der Anteil älterer und alter Menschen an der Gesamtbevölkerung steigt kontinuierlich an. Diese Entwicklung wird sich auch in den kommenden Jahren fortsetzen. So werden 2050 rund 40 % der deutschen Bevölkerung 60 Jahre oder älter sein. Die Alterung der Bevölkerung wirkt sich auf nahezu alle Lebensbereiche aus und stellt damit Planer und Entscheider auf staatlicher wie auf privater Seite vor neue Herausforderungen. Dies betrifft auch die Frage, wie innerstädtische Einkaufsstandorte, und zwar traditionelle innerstädtische Einkaufsstraßen und innerstädtische Shopping Center, gestaltet werden müssen, um den Anforderungen und Bedürfnissen möglichst aller Altersgruppen und damit auch denjenigen der älteren und alten Konsumenten zu entsprechen.
Am Beispiel der Städte Erlangen, Koblenz und Zwickau wird in vorliegender Untersuchung der Frage nachgegangen, wie ältere und alte Menschen die verschiedenen innerstädtischen Einkaufsstandorte wahrnehmen und nutzen, welche Unterschiede diesbezüglich zu jüngeren Kundengruppen bestehen und welche Schlussfolgerungen sich daraus für eine zukunftsgerichtete Gestaltung der traditionellen Einkaufsstraßen und der innerstädtischen Shopping Center ableiten lassen. Für die Untersuchung kam ein breites methodisches Instrumentarium aus Zeitungsrecherchen, Kartierungen, qualitativen Beobachtungen, qualitativen Haushaltsbefragungen sowie quantitativen Passantenbefragungen zur Anwendung.
Die 15 deutschen UNESCO-Biosphärenreservate sollen als Modellregionen eine nachhaltige Entwicklung verwirklichen, wozu neben dem Schutz des Naturhaushaltes und der genetischen Ressourcen auch die sozio-ökonomische Entwicklung der Region zu gewährleisten ist. Als Zielgebiete touristischer Nachfrage stellt der Tourismus potentiell eine Entwicklungschance, und laut den deutschen MAB-Kriterien, ein relevantes Handlungsfeld für die Biosphärenreservats-Verwaltungen dar. Die vorliegende Arbeit behandelt aus zwei unterschiedlichen Perspektiven die Frage, inwieweit Tourismus zur nachhaltigen Regionalentwicklung in den deutschen Biosphärenreservaten beiträgt.
Zum einen wird mittels einer Wertschöpfungsanalyse die touristische Nachfrage und dadurch ausgelöste regionalökonomische Effekte untersucht, was eine Erfassung der Besucher hinsichtlich Anzahl, Strukturen, Ausgabenniveaus, Aufenthaltsmerkmalen sowie Einstellungen umfasst. Zum anderen wird ermittelt, inwieweit die Biosphärenreservats-Verwaltungen die touristische Entwicklung auf regionaler Ebene im Sinne der nachhaltigen Regionalentwicklung mitgestalten. Basierend auf einer touristischen Typisierung der deutschen Biosphärenreservate werden hierzu sechs ausgewählte Biosphärenreservate (Pfälzerwald, Rhön, Schaalsee, Spreewald, Südost-Rügen, Vessertal-Thüringer Wald) eingehend untersucht.
Die Ergebnisse zeigen, dass die Besucherzahlen zwischen 487.000 im Vessertal-Thüringer Wald und 6,4 Mio. in der Rhön schwanken. Insgesamt wird in den sechs Gebieten ein Bruttoumsatz von 908 Mio. € generiert, was einer Wertschöpfung von 474 Mio. € und 28.000 Einkommensäquivalenten entspricht. Der Wert relativiert sich, betrachtet man die Biosphärenreservatsbesucher im engeren Sinn, die für rund 7 % des Bruttoumsatzes bzw. 1.917 Einkommensäquivalente verantwortlich sind. Das Segment ist tendenziell schwach vertreten, jedoch empfänglich für die Ansätze der nachhaltigen Ausrichtung des Tourismus seitens der Biosphärenreservats-Verwaltung. Es präferiert z.B. traditionelle Kulturlandschaftsbilder, Bio-Labels und Regionalität bei Produkten und ist offen gegenüber Schutzbemühungen, was sich jedoch noch nicht im Ausgabeverhalten widerspiegelt.
Hier setzen die Verwaltungen der Biosphärenreservate im Tourismus an und werden auf Destinationsebene im Bereich der strategischen Planung, der Fördermittelakquise, der Generierung touristischer Angebote und Dienstleistungen, der Entwicklung von Regionalvermarktungs- und Partner-Initiativen sowie der Positionierung des Biosphärenreservates als Destination und Marke aktiv. Dennoch wird in allen Gebieten nahezu ausnahmslos die Integration des Biosphärenreservates als Akteur, Attraktion und Angebotsfamilie und verbindende Thematik auf Destinationsebene als verbesserungswürdig eingestuft. Im Rahmen der Arbeit können dafür relevante Faktoren abgeleitet werden, die somit Ansatzpunkte darstellen, den noch ausbaufähigen Beitrag des Tourismus zur nachhaltigen Regionalentwicklung in Biosphärenreservaten im Sinne tangibler und intangibler Effekte zu steigern.
Due to their negative water budget most recent semi-/arid regions are characterized by vast evaporates (salt lakes and salty soils). We recently identified those hyper-saline environments as additional sources for a multitude of volatile halogenated organohalogens (VOX). These compounds can affect the ozone layer of the stratosphere and play a key role in the production of aerosols. A remote sensing based analysis was performed in the Southern Aral Sea basin, providing information of major soil types as well as their extent and spatial and temporal evolution. VOX production has been determined in dry and moist soil samples after 24 h. Several C1- and C2 organohalogens have been found in hyper-saline topsoil profiles, including CH3Cl, CH3Br, CHBr3 and CHCl3. The range of organohalogens also includes trans-1,2-dichloroethene (DCE), which is reported here to be produced naturally for the first time. Using MODIS time series and supervised image classification a daily production rate for DCE has been calculated for the 15 000 km\(^2\) ranging research area in the southern Aralkum. The applied laboratory setup simulates a short-term change in climatic conditions, starting from dried-out saline soil that is instantly humidified during rain events or flooding. It describes the general VOX production potential, but allows only for a rough estimation of resulting emission loads. VOX emissions are expected to increase in the future since the area of salt affected soils is expanding due to the regressing Aral Sea. Opportunities, limits and requirements of satellite based rapid change detection and salt classification are discussed.
This study investigates a two component decomposition technique for HH/VV-polarized PolSAR (Polarimetric Synthetic Aperture Radar) data. The approach is a straight forward adaption of the Yamaguchi decomposition and decomposes the data into two scattering contributions: surface and double bounce under the assumption of a negligible vegetation scattering component in Tundra environments. The dependencies between the features of this two and the classical three component Yamaguchi decomposition were investigated for Radarsat-2 (quad) and TerraSAR-X (HH/VV) data for the Mackenzie Delta Region, Canada. In situ data on land cover were used to derive the scattering characteristics and to analyze the correlation among the PolSAR features. The double bounce and surface scattering features of the two and three component scattering model (derived from pseudo-HH/VV- and quad-polarized data) showed similar scattering characteristics and positively correlated-R2 values of 0.60 (double bounce) and 0.88 (surface scattering) were observed. The presence of volume scattering led to differences between the features and these were minimized for land cover classes of low vegetation height that showed little volume scattering contribution. In terms of separability, the quad-polarized Radarsat-2 data offered the best separation of the examined tundra land cover types and will be best suited for the classification. This is anticipated as it represents the largest feature space of all tested ones. However; the classes “wetland” and “bare ground” showed clear positions in the feature spaces of the C- and X-Band HH/VV-polarized data and an accurate classification of these land cover types is promising. Among the possible dual-polarization modes of Radarsat-2 the HH/VV was found to be the favorable mode for the characterization of the aforementioned tundra land cover classes due to the coherent acquisition and the preserved co-pol. phase. Contrary, HH/HV-polarized and VV/VH-polarized data were found to be best suited for the characterization of mixed and shrub dominated tundra.
The Sentinel-1 Satellite (S-1) of ESA's Copernicus Mission delivers freely available C-Band Synthetic Aperture Radar (SAR) data that are suited for interferometric applications (InSAR). The high geometric resolution of less than fifteen meter and the large coverage offered by the Interferometric Wide Swath mode (IW) point to new perspectives on the comprehension and understanding of surface changes, the quantification and monitoring of dynamic processes, especially in arid regions. The contribution shows the application of S-1 intensities and InSAR coherences in time series analysis for the delineation of changes related to fluvial morphodynamics in Damghan, Iran. The investigations were carried out for the period from April to October 2015 and exhibit the potential of the S-1 data for the identification of surface disturbances, mass movements and fluvial channel activity in the surroundings of the Damghan Playa. The Amplitude Change Detection highlighted extensive material movement and accumulation - up to sizes of more than 4,000 m in width - in the east of the Playa via changes in intensity. Further, the Coherence Change Detection technique was capable to indicate small-scale channel activity of the drainage system that was neither recognizable in the S-1 intensity nor the multispectral Landsat-8 data. The run off caused a decorrelation of the SAR signals and a drop in coherence. Seen from a morphodynamic point of view, the results indicated a highly dynamic system and complex tempo-spatial patterns were observed that will be subject of future analysis. Additionally, the study revealed the necessity to collect independent reference data on fluvial activity in order to train and adjust the change detector.
Der demographische Wandel stellt in den meisten entwickelten Ländern einen externen Treiber dar, der die Entwicklung in und um Nationalparke in Zukunft maßgeblich mitbestimmen wird. Die Alterung der Besucher, die in den nächsten beiden Jahrzehnten die dominante Komponente des demographischen Wandels in Deutschland darstellen dürfte, erfordert von Seiten der Nationalparke eine Anpassung ihrer Besuchermanagementaktivitäten auch im Bereich der Infrastruktur. Hierfür muss jedoch zunächst grundlegendes Wissen über die Altersabhängigkeit raumzeitlichen Verhaltens vorhanden sein. Die zentrale forschungsleitende Frage der vorliegenden Arbeit ist in diesem Kontext angesiedelt und versucht herauszuarbeiten, in welcher Art auftretende Alterseffekte bei der körperlichen Leistungsfähigkeit sowohl die Tourenoptionen im Raum als auch das tatsächliche raumzeitliche Verhalten beeinflussen. Als Untersuchungsgebiet wurde mit dem Nationalpark Berchtesgaden der einzige alpine Nationalpark Deutschlands gewählt. Dieser besitzt aufgrund seiner Topographie ein breites Spektrum an Tourenmöglichkeiten mit unterschiedlichsten Anforderungen an die körperliche Leistungsfähigkeit. Aufbauend auf den theoretischen Erklärungszugängen der Time-Geography und des Constraints-Konzeptes der Freizeitforschung wurde zur Beantwortung der Forschungsfragen ein Methodenmix aus standardisierter Befragung und GPS-Logging zur Aufnahme des Tourenwahlverhaltens eingesetzt. Die gewonnenen Trajektorien wurden mit weiteren Informationen zur Ausstattung des Raumes versehen, um eine detailliertere Beschreibung des raumzeitlichen Verhaltens zu ermöglichen.
Die Analysen zeigen, dass im Nationalpark Berchtesgaden vier Aktivitätstypen mit abweichendem raumzeitlichem Verhalten unterschieden werden können. Nur eine Minderheit von ca. einem Drittel der Besucher wählt dabei Touren, die mit größerer körperlicher Anstrengung verbunden sind. Die restlichen Besucher wandern nur halbtags oder kürzer im Gebiet und überwinden dabei nur wenige Höhenmeter. Im Altersverlauf konnten klare Brüche im raumzeitlichen Verhalten identifiziert werden. So verliert der Aktivitätstypus des Bergsteigers, der sich durch die Begehung alpiner Wege mit Absturzgefahr auszeichnet, bereits ab einem Alter von 50 Jahren stark an Bedeutung. Ab 60 Jahren steigt der Anteil sehr kurzer Touren sprunghaft. Ursachen dieser Veränderungen liegen primär in der Wahrnehmung von eingeschränkter körperlicher Leistungsfähigkeit, sowie einer veränderten Motivationsstruktur.
Diese abweichenden Muster raumzeitlichen Verhaltens sind jedoch auch das Resultat divergierender Tourenoptionen. So konnte gezeigt werden, dass ältere Besucher aufgrund der niedrigen Fortbewegungsgeschwindigkeit nur einen geringeren Anteil der Wege im Nationalpark innerhalb eines bestimmten Zeitbudgets erreichen können.
Wird die Verteilung der Aktivitätstypen unter der Annahme eines ausschließlich wirkenden Alterseffektes in die Zukunft übertragen, bedeutet dies eine Steigerung der Besucherkonzentration in der Managementzone des Nationalparks und eine Bedeutungszunahme von stationären Aktivitäten.
Cropping Intensity in the Aral Sea Basin and Its Dependency from the Runoff Formation 2000–2012
(2016)
This study is aimed at a better understanding of how upstream runoff formation affected the cropping intensity (CI: number of harvests) in the Aral Sea Basin (ASB) between 2000 and 2012. MODIS 250 m NDVI time series and knowledge-based pixel masking that included settlement layers and topography features enabled to map the irrigated cropland extent (iCE). Random forest models supported the classification of cropland vegetation phenology (CVP: winter/summer crops, double cropping, etc.). CI and the percentage of fallow cropland (PF) were derived from CVP. Spearman’s rho was selected for assessing the statistical relation of CI and PF to runoff formation in the Amu Darya and Syr Darya catchments per hydrological year. Validation in 12 reference sites using multi-annual Landsat-7 ETM+ images revealed an average overall accuracy of 0.85 for the iCE maps. MODIS maps overestimated that based on Landsat by an average factor of ~1.15 (MODIS iCE/Landsat iCE). Exceptional overestimations occurred in case of inaccurate settlement layers. The CVP and CI maps achieved overall accuracies of 0.91 and 0.96, respectively. The Amu Darya catchment disclosed significant positive (negative) relations between upstream runoff with CI (PF) and a high pressure on the river water resources in 2000–2012. Along the Syr Darya, reduced dependencies could be observed, which is potentially linked to the high number of water constructions in that catchment. Intensified double cropping after drought years occurred in Uzbekistan. However, a 10 km × 10 km grid of Spearman’s rho (CI and PF vs. upstream runoff) emphasized locations at different CI levels that are directly affected by runoff fluctuations in both river systems. The resulting maps may thus be supportive on the way to achieve long-term sustainability of crop production and to simultaneously protect the severely threatened environment in the ASB. The gained knowledge can be further used for investigating climatic impacts of irrigation in the region.
This study analyzed the spatiotemporal pattern of settlement expansion in Abuja, Nigeria, one of West Africa’s fastest developing cities, using geoinformation and ancillary datasets. Three epochs of Land-use Land-cover (LULC) maps for 1986, 2001 and 2014 were derived from Landsat images using support vector machines (SVM). Accuracy assessment (AA) of the LULC maps based on the pixel count resulted in overall accuracy of 82%, 92% and 92%, while the AA derived from the error adjusted area (EAA) method stood at 69%, 91% and 91% for 1986, 2001 and 2014, respectively. Two major techniques for detecting changes in the LULC epochs involved the use of binary maps as well as a post-classification comparison approach. Quantitative spatiotemporal analysis was conducted to detect LULC changes with specific focus on the settlement development pattern of Abuja, the federal capital city (FCC) of Nigeria. Logical transitions to the urban category were modelled for predicting future scenarios for the year 2050 using the embedded land change modeler (LCM) in the IDRISI package. Based on the EAA, the result showed that urban areas increased by more than 11% between 1986 and 2001. In contrast, this value rose to 17% between 2001 and 2014. The LCM model projected LULC changes that showed a growing trend in settlement expansion, which might take over allotted spaces for green areas and agricultural land if stringent development policies and enforcement measures are not implemented. In conclusion, integrating geospatial technologies with ancillary datasets offered improved understanding of how urbanization processes such as increased imperviousness of such a magnitude could influence the urban microclimate through the alteration of natural land surface temperature. Urban expansion could also lead to increased surface runoff as well as changes in drainage geography leading to urban floods.
Schutzgebiete und insbesondere Nationalparke haben nach den Richtlinien der IUCN ein Doppelmandat bzw. eine doppelte Funktion: Sie sollen zum einen Räume für Natur- und Artenschutz und zum anderen für Erholung, Umweltbildung und Tourismus bieten und durch letztgenanntes zur Stärkung der Regionalökonomie beitragen. Um diesen Spagat zu meistern, sollten sich Schutzgebiete bzw. deren Verwaltungen und kooperierende Destinationsmarketingorganisationen darüber im Klaren sein, welche Besuchersegmente bzw. Tourismusprodukte im Schutzgebiet anzutreffen sind, bzw. angeboten werden und welchen Einfluss diese auf die Erfüllung des Doppelmandates haben. Die deduktiv entworfene Product-based Typology for Nature-based Tourism von ARNEGGER et al. (2010) bietet hierfür einen zweidimensionalen Analyserahmen, der die Angebots- und Nachfrageperspektive auf den Tourismus und dessen Produkte vereint und bisher noch nicht empirisch angewendet wurde, was das vorrangige Ziel dieser Studie ist.
Hierfür wurde von Theorien und empirischen Studien aus dem Kontext von Natur- und Ökotourismus eine Operationalisierung der Typologie abgeleitet, die am Beispiel des Nationalparks Berchtesgaden eingesetzt wurde. Dabei wurden zwei Ansätze verfolgt, eine angebotsseitige und eine nachfrageseitige Abgrenzung von Tourismusprodukten. Zur empirischen Erfassung von Tourismusprodukten wurde eine umfassende Besucherbefragung in der Sommersaison 2014 durchgeführt, bei der Informationen von rund 1.400 Besuchern des Nationalparks gesammelt werden konnten.
Aus Sicht der Nachfrager wurden sechs Produkt-Cluster identifiziert, die sich bezüglich Reiseaktivitäten und Motiven unterscheiden. Das mit der höchsten Naturaffinität ist das Produkt-Cluster der „Naturbildungsurlauber“ bzw. der „Ökotouristen“. Auf der anderen Seite des Spektrums stehen die „Passiven Erholungsurlauber“ mit einer geringen Nationalparkaffinität. Des Weiteren wurden spezifische Tourismusprodukte aus der Angebotsperspektive, wie Exkursionen der Nationalparkverwaltung oder mehrtägige geführte Wanderungen von spezialisierten Nischenreiseveranstaltern, identifiziert.
Nach der empirischen Abgrenzung der Produkte wurden diese dahingehend überprüft, ob sie sich bezüglich ökonomischer und ökologischer Indikatoren unterscheiden, um zu eruieren, inwieweit die Segmente aus Sicht einer nachhaltigen Regionalentwicklung bzw. aus Sicht des Doppelmandats zu beurteilen sind. Auch hier schneiden etwa die Naturbildungsurlauber relativ gut ab, da sie Muster von structured ecotourism aufweisen und sich durch eine hohe Naturaffinität, positive Einstellungen zu nachhaltigem Tourismus und relativ hohe Reiseausgaben auszeichnen. Bei drei Clustern zeigt sich ein gewisser trade-off: Während die Bergsteiger aus ökologischer jedoch nicht aus ökonomischer Perspektive interessant sind, ist dies bei den allgemeinen Vergnügungs- und Naturerlebnisurlaubern und den passiven Erholungsurlaubern genau umgekehrt.
Basierend auf den Ergebnissen werden mögliche Adaptionen der Typologie diskutiert und darauf aufbauend ein Analyserahmen für eine „Typologie für Nachhaltige Park-Tourismus Produkte“ erarbeitet. Zudem werden theoretische und erste praktische Implikationen für das Management von Schutzgebiets-Destinationen diskutiert, um unter Berücksichtigung der trade-offs das Produktportfolio weiterzuentwickeln, das eine Destination auf den Pfad des sogenannten enlightened mass tourism bringen kann.
The 2007 flood in the Sahel: causes, characteristics and its presentation in the media and FEWS NET
(2012)
During the rainy season in 2007, reports about exceptional rains and floodings in the Sahel were published in the media, especially in August and September. Institutions and organizations like the World Food Programme (WFP) and FEWS NET put the events on the agenda and released alerts and requested help. The partly controversial picture was that most of the Sahel faced a crisis caused by widespread floodings. Our study shows that the rainy season in 2007 was exceptional with regard to rainfall amount and return periods. In many areas the event had a return period between 1 and 50 yr with high spatial heterogeneity, with the exception of the Upper Volta basin, which yielded return periods of up to 1200 yr. Despite the strong rainfall, the interpretation of satellite images show that the floods were mainly confined to lakes and river beds. However, the study also proves the difficulties in assessing the meteorological processes and the demarcation of flooded areas in satellite images without ground truthing. These facts and the somewhat vague and controversial reports in the media and FEWS NET demonstrate that it is crucial to thoroughly analyze such events at a regional and local scale involving the local population.
Objective: The objective of this study was to investigate the applicability of microanalytical methods with high spatial resolution to the characterization of the composition and corrosion behavior of two bracket systems.
Material and methods: The surfaces of six nickel-free brackets and six nickel-containing brackets were examined for signs of corrosion and qualitative surface analysis using an electron probe microanalyzer (EPMA), prior to bonding to patient's tooth surfaces and four months after clinical use. The surfaces were characterized qualitatively by secondary electron (SE) images and back scattered electron (BSE) images in both compositional and topographical mode. Qualitative and quantitative wavelength-dispersive analyses were performed for different elements, and by utilizing qualitative analysis the relative concentration of selected elements was mapped two-dimensionally. The absolute concentration of the elements was determined in specially prepared brackets by quantitative analysis using pure element standards for calibration and calculating correction-factors (ZAF).
Results: Clear differences were observed between the different bracket types. The nickel-containing stainless steel brackets consist of two separate pieces joined by a brazing alloy. Compositional analysis revealed two different alloy compositions, and reaction zones on both sides of the brazing alloy. The nickel-free bracket was a single piece with only slight variation in element concentration, but had a significantly rougher surface. After clinical use, no corrosive phenomena were detectable with the methods applied. Traces of intraoral wear at the contact areas between the bracket slot and the arch wire were verified. Conclusion: Electron probe microanalysis is a valuable tool for the characterization of element distribution and quantitative analysis for corrosion studies.
Advancing land degradation in the irrigated areas of Central Asia hinders sustainable development of this predominantly agricultural region. To support decisions on mitigating cropland degradation, this study combines linear trend analysis and spatial logistic regression modeling to expose a land degradation trend in the Khorezm region, Uzbekistan, and to analyze the causes. Time series of the 250-m MODIS NDVI, summed over the growing seasons of 2000–2010, were used to derive areas with an apparent negative vegetation trend; this was interpreted as an indicator of land degradation. About one third (161,000 ha) of the region’s area experienced negative trends of different magnitude. The vegetation decline was particularly evident on the low-fertility lands bordering on the natural sandy desert, suggesting that these areas should be prioritized in mitigation planning. The results of logistic modeling indicate that the spatial pattern of the observed trend is mainly associated with the level of the groundwater table (odds = 330 %), land-use intensity (odds = 103 %), low soil quality (odds = 49 %), slope (odds = 29 %), and salinity of the groundwater (odds = 26 %). Areas, threatened by land degradation, were mapped by fitting the estimated model parameters to available data. The elaborated approach, combining remote-sensing and GIS, can form the basis for developing a common tool for monitoring land degradation trends in irrigated croplands of Central Asia.
Diese Arbeit widmet sich detaillierten stratigraphischen und paläopedologischen Studien an Löss-Paläoboden Sequenzen (LPS) im kontinentalen Nordosten Österreichs, im Lee der Böhmischen Masse relativ zur Westwindzone. Neben methodischen Erkenntnissen ergeben sich allgemeine Schlussfolgerungen über die Klima- und Landschaftsentwicklung während der letzten Million Jahre.
Die untersuchten Aufschlüsse liegen in der Region um Krems (Krems-Schießstätte, Paudorf, Stiefern) und in Stillfried. Einige sind weithin bekannt als ehemalige Typuslokalitäten der Quartärstratigraphie, aber nach fundamentalen Revisionen in den 1970er Jahren schwand das Interesse an diesen merklich. Die LPS befinden sich in Hanglage, so sind polygenetische Einheiten und Erosionslücken üblich. Als Archive einer komplexen geomorphologischen Entwicklung sind sie nicht geeignet für die Anwendung üblicher paläoklimatischer Proxies.
Um die Entstehung der untersuchten LPS zu verstehen, wurde ein multimethodischer Ansatz entwickelt, der detaillierte Untersuchungen von der Landschafts- bis auf die Mikroebene umfasst. Innovativ ist die Verwendung quantitativer Farbmessungen in hoher Auflösung zum Zwecke einer standardisierten Klassifikation von Profileinheiten. Detaillierte mikromorphologische Untersuchungen sind Basis für die Rekonstruktion des Wechselspiels aus äolischer Sedimentation, Pedogenese und Hangprozessen.
Die Korrelation der LPS basiert auf mehreren geochronologischen Ankerpunkten und ist zugleich Hinweis auf tiefgreifende morphologische Veränderungen in der Region Krems während des Pleistozäns. Im chronologischen Rahmen ergeben sich unter Anwendung des Konzepts der klimaphytomorphen Böden qualitative paläoklimatische Schlussfolgerungen:
Kräftig verwitterte Bodenhorizonte sind polygenetisch und nicht das Resultat feuchterer Klimabedingungen während dezidierter Entwicklungsphasen. Die Kontinentalität des Untersuchungsgebiets blieb währenden der letzten Million Jahre weitgehend bestehen, teils mit erhöhtem mediterranem Einfluss. Eine Dominanz atlantischer Feuchte beschränkt(e) sich auf die Regionen westlich der Böhmischen Masse. Die Paläoklimate des Untersuchungs-gebiets waren eher vergleichbar mit jenen des Pannonischen Beckens, obgleich die untersuchten Sequenzen keinen Hinweis auf den dort vermuteten Gradienten zunehmender Aridität zeigen. Interessant sind ferner zahlreiche gebleichte Horizonte innerhalb der Lösssedimente, die als Reste von Tundragleyen interpretiert werden. Diese sind im Löss des Pannonischen Becken nicht nachweisbar. Hieraus wird ein mitteleuropäischer Charakter kaltzeitlichen Klimas innerhalb des untersuchten Zeitrahmens gefolgert.
Massenbewegungen zählen zu den am häufigsten auftretenden Naturgefahren in Deutschland. Dabei wird die von instabilen Hängen ausgehende Gefährdung speziell in den Regionen der Mittelgebirge regelmäßig unterschätzt. In Bezug auf die Verbreitung von Massenbewegungen in Mittelgebirgen stellt das süddeutsche Schichtstufenland einen besonderen Schwerpunkt dar.
Die Disposition der Schichtstufenhänge beruht dabei in erster Linie auf einer Wechsellagerung wasserdurchlässiger und wasserstauender geologischer Schichten. Zu Hanginstabilitäten kommt es bevorzugt in Verbindung mit synthetischem Schichtfallen, steilen Hängen und erhöhten Niederschlägen. Rezente Massenbewegungen treten verstärkt in alten Rutsch- und/oder Hangschuttgebieten auf, da sich dort unkonsolidierte Rutschmassen leicht remobilisieren lassen.
Das Ziel der vorliegenden Arbeit ist es, ein fundiertes Verständnis über Ursachen, Ablauf, Ausprägung und Prozesse von charakteristischen Massenbewegungen sowie dem aktuellen Aufbau der damit verbundenen Schichtstufenhänge in Nordbayern zu erlangen, um daraus grundlegende Einschätzungen zur Stabilität der Rutschgebiete treffen zu können. Neben den rutschungsrelevanten geologischen Schichten sind in diesem Zusammenhang insbesondere der Aufbau, die Eigenschaften und Charakteristika der Rutschmassen von besonderer Wichtigkeit, da besonders die bodenmechanischen und bodenphysikalischen Eigenschaften einen entscheidenden Faktor in Bezug auf die Hangstabilität darstellen. Entsprechend steht die umfassende Analyse dieser Sedimente im Fokus der Studien.
Die Arbeiten betrachten dabei drei Hänge im fränkischen Schichtstufenland, an denen in der jüngeren Vergangenheit Massenbewegungen auftraten. Ein weiteres zentrales Auswahlkriterium war die Lage der Gebiete in den Schichtstufen der Fränkischen Alb und der westlich vorgelagerten Keuperstufe, wobei hinsichtlich Typ und Verbreitung möglichst charakteristische Massenbewegungen für die jeweilige Region ausgewählt wurden. Bei Ebermannstadt stand demnach die sog. Werkkalkstufe der Weißjura-Kalke im Fokus, nahe Wüstendorf die Sandsteine des Braunjura und bei Gailnau an der Frankenhöhe die Sandsteine des mittleren (Gips-) Keupers.
Die Untersuchungen der Rutschungen und ihrer Sedimentcharakteristika erfolgte anhand eines speziell konzipierten Multimethodenansatzes mit zahlreichen, multiskaligen Gelände- und Laboranalysen. Neben klassischen, geomorphologischen Kartierungen an der Oberfläche wurden die sedimentologisch-morphologischen Verhältnisse des oberflächennahen Untergrundes in der Vertikalen durch geophysikalische Sondierungen analysiert. Eine Einschätzung der hydrologischen Verhältnisse der Rutschmassen erfolgte auf Basis von Messdaten aus Bodenfeuchtemonitoringsystemen, die an allen Untersuchungsstandorten installiert wurden. Für die bodenphysikalischen und -mechanischen Eigenschaften der Sedimente wurden Korngrößen, Konsistenzgrenzen, Plastizität, Gefüge und Lagerungsdichte untersucht und durch Tonmineralanalysen ergänzt. Die mikromorphologische Analyse von Dünnschliffen aus Rutschungssedimenten und den darin enthaltenen Deformationsstrukturen erweiterten den Gesamtansatz, ermöglichten neuartige Einblicke in die innere Architektur von Rutschmassen und erlaubten die Rekonstruktion von Bewegungsabläufen.
Durch die Arbeiten konnten an den Standorten Ebermannstadt und Gailnau komplexe, vielschichtige Massenbewegungen nachgewiesen werden. In der Rutschung bei Wüstendorf wurden nahezu ausschließlich unkonsolidierte Sedimente feinerer Korngrößen in einem Fließprozess verlagert. Primär erfolgte bei allen Rutschungen nachweislich die Remobilisierung alter Hangsedimente, wobei darüber hinaus auch stets bisher stabile Areale mit in die Bewegung einbezogen wurden.
Der sedimentologische Aufbau der Rutschmassen ist speziell im Falle großer und komplexer Rutschungen mitunter extrem heterogen. Im Zuge der Arbeiten konnten interne Makrostrukturen der Sedimentablagerungen, wie beispielsweise Rotationsflächen oder die Lage von Schollen detektiert werden. Trotz geophysikalisch und visuell auffälliger Beimischungen von Grobschutt, entfallen die größten Mengenanteile aber stets auf die veränderlich feste Feinmaterialfraktion. Im Rahmen der mikromorphologischen Untersuchungen der Sedimentdünnschliffe konnten auch in diesen Sedimenten zahlreiche Deformationsstrukturen nachgewiesen werden.
Die Arbeit unterstreicht insgesamt die Bedeutung dieser bindigen Bestandteile für die (Re)Mobilisierung von Sedimentablagerungen. Die Stabilität des Feinmaterials steht dabei in engem Zusammenhang mit der hydraulischen Leitfähigkeit und dem Eintrag von Wasser, welches zu wechselnden Steifigkeiten der Sedimente führt. Im Falle erhöhter Bodenwassergehalte konnte eine Plastifizierung der Feinkornfraktion ermittelt werden. Kommt es zu einer starken Durchnässung des Untergrundes, führt dies zu einer Plastifizierung der tonigen Lagen und einer entsprechenden Reduktion der Scherfestigkeit, was letztlich zum Auslösen von Massenbewegungen führt. Neben den geologisch-sedimentologischen Voraussetzungen impliziert dies auch eine hohe Bedeutung der Niederschlagscharakteristika in Bezug auf das Auslösen rezenter Massenbewegungen.
Die Bodenwassergehalte unterliegen im Jahresverlauf einer deutlichen saisonalen Variabilität. Während der Sommermonate wurden einheitlich niedrige Feuchtigkeitswerte im oberflächennahen Untergrund verzeichnet, was in erster Linie auf den Einfluss der Vegetation zurückzuführen ist. Auch sommerliche Starkregenereignisse besitzen unter diesen Bedingungen lediglich eine reduzierte Wirkung auf die Durchfeuchtung des Bodens. Demgegenüber erfolgt während der kalten Jahreszeit ein signifikanter Anstieg der Bodenwassergehalte. Neben den Regenfällen kommt vor allem der Schneeschmelze eine essentielle Bedeutung zu, da sie für eine zusätzliche und anhaltende Durchfeuchtung der Schichten besonders im Spätwinter bzw. Frühjahr sorgt. Entsprechend besteht vor allem während der Monate Februar bis April eine erhöhte Disposition für Rutschungen in Nordbayern. Im Hinblick auf die Niederschlagssummen gingen den Rutschungen in den Untersuchungsgebieten zwar keine besonders extremen Ereignisse, aber durchaus deutlich überdurchschnittliche Niederschlagssummen voraus, weshalb unter Berücksichtigung der im Zuge des Klimawandels ansteigenden Winterniederschläge von einer generell verstärkten Rutschungsaktivität auszugehen ist.
Vergleiche mit den Daten aus zahlreichen Übersichtskartierungen von Rutschungen aus den fränkischen Schichtstufengebieten verdeutlichen, dass die ermittelten Ergebnisse auf eine Vielzahl der verzeichneten Rutschungen übertragbar sind.
The 2010 eruption of Eyjafjallajokull volcano was characterized by pulsating activity. Discrete ash bursts merged at higher altitude and formed a sustained quasi-continuous eruption column. High-resolution near-field videos were recorded on 8-10 May, during the second explosive phase of the eruption, and supplemented by contemporary aerial observations. In the observed period, pulses occurred at intervals of 0.8 to 23.4 s (average, 4.2 s). On the basis of video analysis, the pulse volume and the velocity of the reversely buoyant jets that initiated each pulse were determined. The expansion history of jets was tracked until the pulses reached the height of transition from a negatively buoyant jet to a convective buoyant plume about 100 m above the vent. Based on the assumption that the density of the gas-solid mixture making up the pulse approximates that of the surrounding air at the level of transition from the jet to the plume, a mass flux ranging between 2.2 and 3.5 . 10\(^4\) kg/s was calculated. This mass eruption rate is in good agreement with results obtained with simple models relating plume height with mass discharge at the vent. Our findings indicate that near-field measurements of eruption source parameters in a pulsating eruption may prove to be an effective monitoring tool. A comparison of the observed pulses with those generated in calibrated large-scale experiments reveals very similar characteristics and suggests that the analysis of near-field sensors could in the future help to constrain the triggering mechanism of explosive eruptions.
Cu- and Mn-bearing tourmalines from Brazil and Mozambique were characterised chemically (EMPA and LA-ICP-MS) and by X-ray single-crystal structure refinement. All these samples are rich in Al, Li and F (fluor-elbaite) and contain significant amounts of CuO (up to ~1.8 wt%) and MnO (up to ~3.5 wt%). Structurally investigated samples show a pronounced positive correlation between the <Y-O> distances and the (Li + Mn\(^{2+}\) + Cu + Fe\(^{2+}\)) content (apfu) at this site with R\(^2\) = 0.90. An excellent negative correlation exists between the <Y-O> distances and the Al\(_2\)O\(_3\) content (R\(^2\) = 0.94). The samples at each locality generally show a strong negative correlation between the X-site vacancies and the (MnO + FeO) content. The Mn content in these tourmalines depends on the availability of Mn, on the formation temperature, as well as on stereochemical constraints. Because of a very weak correlation between MnO and CuO we believe that the Cu content in tourmaline is essentially dependent on the availability of Cu and on stereochemical constraints.
Rice is the most important food crop in Asia, and the timely mapping and monitoring of paddy rice fields subsequently emerged as an important task in the context of food security and modelling of greenhouse gas emissions. Rice growth has a distinct influence on Synthetic Aperture Radar (SAR) backscatter images, and time-series analysis of C-band images has been successfully employed to map rice fields. The poor data availability on regional scales is a major drawback of this method. We devised an approach to classify paddy rice with the use of all available Envisat ASAR WSM (Advanced Synthetic Aperture Radar Wide Swath Mode) data for our study area, the Mekong Delta in Vietnam. We used regression-based incidence angle normalization and temporal averaging to combine acquisitions from multiple tracks and years. A crop phenology-based classifier has been applied to this time series to detect single-, double- and triple-cropped rice areas (one to three harvests per year), as well as dates and lengths of growing seasons. Our classification has an overall accuracy of 85.3% and a kappa coefficient of 0.74 compared to a reference dataset and correlates highly with official rice area statistics at the provincial level (R-2 of 0.98). SAR-based time-series analysis allows accurate mapping and monitoring of rice areas even under adverse atmospheric conditions.
An Overview of the Regional Experiments for Land-atmosphere Exchanges 2012 (REFLEX 2012) Campaign
(2015)
The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy fluxes, soil temperature profiles, soil moisture profiles, surface temperature, canopy structure as well as leaf-level measurements were carried out. Additional thermo-dynamical monitoring took place at selected sites. After presenting the different types of measurements, some examples are given to illustrate the potential of the observations made.
This study aimed to optimise the application, efficiency and interpretability of quasi-3D resistivity imaging for investigating the heterogeneous permafrost distribution at mountain sites by a systematic forward modelling approach. A three dimensional geocryologic model, representative for most mountain permafrost settings, was developed. Based on this geocryologic model quasi-3D models were generated by collating synthetic orthogonal 2D arrays, demonstrating the effects of array types and electrode spacing on resolution and interpretability of the inversion results. The effects of minimising the number of 2D arrays per quasi-3D grid were tested by enlarging the spacing between adjacent lines and by reducing the number of perpendicular tie lines with regard to model resolution and loss of information value. Synthetic and measured quasi-3D models were investigated with regard to the lateral and vertical resolution, reliability of inverted resistivity values, the possibility of a quantitative interpretation of resistivities and the response of the inversion process on the validity of quasi-3D models. Results show that setups using orthogonal 2D arrays with electrode spacings of 2 m and 3 m are capable of delineating lateral heterogeneity with high accuracy and also deliver reliable data on active layer thickness. Detection of permafrost thickness, especially if the permafrost base is close to the penetration depth of the setups, and the reliability of absolute resistivity values emerged to be a weakness of the method. Quasi-3D imaging has proven to be a promising tool for investigating permafrost in mountain environments especially for delineating the often small-scale permafrost heterogeneity, and therefore provides an enhanced possibility for aligning permafrost distribution with site specific surface properties and morphological settings.
11 Conclusion
11.1 Glaze compositions
Glazes from tiles of imposing Islamic buildings and some tableware glazes of the medieval epoch in Central Asia, the Middle East, Asia Minor, and North Africa are analysed regarding their main composition and colouring agents. Three major production recipes can be distinguished, i.e. alkali glazes, alkali lead glazes, and lead glazes. In the work of Tite (2011), Islamic glazes from Egypt, Iran, Iraq, and Syria are subdivided into four groups of composition, being partly consistent with those of this work. The alkali lime glazes with <2 wt% PbO correspond to the alkali glazes, but with higher content of CaO. The second and third group of low lead alkali and lead alkali glazes (2-10 wt% PbO and 10-35 wt% PbO) can be subsumed to the alkali lead group described here. Tite´s high lead group has PbO contents >35 wt% and is comparable to the lead glazes (>30 wt% PbO) of this study. The lead and the alkali oxides serve as a flux for the lowering the melting point.
In the interaction of ceramic body and glaze, primarily an influence from Si, Al, and K is observed in the line scans from the cross section of ceramic and glaze. However, the input of ceramic material doesn’t seem to be critical for the classification of glazes according to their alkali and alkali lead compositions.
In every epoch and locality, except of the Ilkhanate dynasty in Iran, lead glaze samples can be verified. This is also observed in previous investigations e.g. from medieval Iraq, Jordan and Iran (McCarthy, 1996; Al-Saad, 2002; Holakooei et al., 2014). In the Moroccan and Bulgarian glazes, lead seems to be the only important flux. In part, the lead flux is supplemented by additional alkali contents. The lack of alkali and alkali lead glazes in Bulgarian and Moroccan glazes (assuming that the Ottoman alkali lead glazes are imported tableware) seems to affect the regions with Roman-influenced history and with geographical distance to the Near East alkali flux tradition.
For the alkali lead glazes and alkali glazes, the overall characteristic is sodium dominated, although the absolute soda values are in part surprisingly low. Samples from Bukhara, Takht-i-Suleiman and the Turkish localities have the highest, but still moderate Na2O values up to 15 wt%, compared to other analyses from e.g. India (Gill & Rehren, 2011).
The source of the alkali flux is either mineral natron or plant ash. The source can be determined regarding the MgO values, limited to 1.3 wt% in mineral natron and exceeding 2.0 wt% in the case of plant ashes. In the samples of the present study, the K2O component is not suitable for the indication of the flux-relevant alkali source due to its broad scattering. The P2O5 contents are also enhanced in the plant ash compositions but the data set is not sufficient for statistical evaluation. An influence of the ceramic body on the glaze composition is observed only for SiO2, Al2O3, and K2O in quartz frit ceramics with slight K-feldspar content.
The earliest Uzbek tableware glazes from the 10th-11th century (Seljuq period) were generally produced using a lead flux. The same applies to part of the Uzbek tile glazes which were produced between the 13th and 16th century. In Iran, glazes from the 12th century (Khwarezmid period) are lead glazes, but also alkali-fluxed glazes with mineral natron characteristics can be found. Although the production of lead-rich glazes was established from the 8th-9th century on in Iraq, Syria, and Egypt (Henshaw, 2010; Tite et al., 2011), alkali glazes are found in almost all regions except of Bulgaria and Morocco.
Plant ash-fluxed alkali glazes are found in 13th century glazes from Takht-i-Suleiman. The plant ash flux technology is assumed to be continuously used in Mesopotamia, Iran, and Central Asia (Sayre & Smith, 1974; Henderson, 2009), but it could be shown that a parallel use of mineral natron parallel existed in the alkali glaze production from the 12th-15th century from Uzbekistan to Afghanistan. Mineral natron characteristics are also reported by Mason (2004) for Syrian and Iranian alkali glazes on lustre ware of the 8th-14th century. Tile glazes with partly mineral natron compositions are found in the Mughal architectural glazes from the 14th- 17th century from India (Gill et al., 2014).
Alkali and alkali lead tile glazes from Samarkand from the 13th century (Mongolian period) have mineral natron flux characteristics, but samples from the 15th century (Timurid period) show plant ash signature. Alkali fluxed Uzbek glazes from Bukhara from the 16th century (Sheibanid dynasty) are also made by plant ash flux and are subdivided into two groups with high and low sodium oxide content. The Afghan alkali glazes have sodium oxide contents similar to the sodium-poor Uzbek subgroup, which points to a possible exchange of glaze makers or glaze making technology from Uzbekistan and Afghanistan in the 15th-17th century. Regarding the extensive exchange of Timurid craftsmen in Central Asia, this option seems to be even more likely (Golombek, 1996). One sample from the 15th century from Afghanistan with mineral natron reveals that this material was parallel used in these centuries.
Concerning the colouring of the glazes, it has to be distinguished between pigments and colouring ions which are incorporated in the glassy matrix. The colouring agents for translucent glazes are cations of various transition metals. As ions, Co2+ (blue), Cu2+ (green in a lead rich matrix), Fe3+ (brown/black), Mn4+ (brown/black) and Mn3+ (violet) are determined by EPMA. For opaque yellow, white, and turquoise glazes, different pigments were used. The crystalline pigments are investigated by a µ XRD2 device with the result of SnO2, SiO2, and PbSiO4 as whitening agents. PbSiO4 and Pb2Sn2O6 are found in the yellow glaze, from which only the lead tin oxide causes the yellow colour. In the black glazes, different Cr-rich pigments, Cu-Cr-Mn-oxides and iron containing clinopyroxenes are found, even in samples of the same period and region. Cr-rich particles are also detected in two turquoise Afghan glazes from the 15th and 16th century. The use of the ions of Fe, Cu, Co, Cr, and Mn seems to be widely common in the Islamic glazes and corresponds to the described colouring agents in e.g. the study of Tite (2011). The use of opacifying SnO2 particles is widespread as it is reported from different Islamic glazes from Iraq, Iran, Egypt, and Syria (Henshaw, 2010; O´Kane, 2011; Tite, 2011). The colouring agents are known already from former, e.g. Egyptian, Roman and pre-islamic periods, but especially SnO2 pigments became increasingly widespread in the Islamic glazing tradition. The use of yellow and black pigments instead varies already within the buildings from Bukhara from Cr crystals and clino-pyroxenes in the mosque Khoja Zainuddin to a Cu-Cr-Mn-oxide in the madrassa Mir-i Arab of the same epoch.
Regarding the matrix compositions connected with the colouring, a certain assignment within the different locations and epochs can be seen. It is noticeable that e.g. the content of lead in turquoise glazes in Uzbekistan is in the range of 0.0-9.2 wt% Pb, whereas blue glazes are mostly alkali ones with PbO contents <2.0 wt%. The turquoise glazes show, that this restriction is not influenced by any defaults of availability and processability. The assumption of common addition of lead and tin to the glaze, which is already described for Iranian glazes of the 13th century (Allan et al., 1973) cannot be confirmed by correlations of tin and lead oxide in the compositions.
11.2 Portable XRF measurement
With the p-XRF, semi-quantitative information about the major element compositions is generated. The depth of the detectable signals depends on the analysed sample setup. The p-XRF data are collected with the XL3 Hybrid device of the company Analyticon Instruments. In the comparison of p-XRF results of the “mining” program from Uzbek glazes with EPMA results, the same major composition groups can be distinguished. The Moroccan glazes, all lead rich, are measured with the “mining” as well as with the “soil” program, revealing a better performance in the “mining” measurements. The deviations are nevertheless high, because of the high lead contents, which make the calculation of matrix correction difficult.
The measurement of the colouring oxides MnO2, CoO, and CuO is satisfying with the internal calibration of the device and even improved with the “mining” program measurement, if compared to the results of the “soil” program. The measurements of glaze imitations lead to better results than that of bulk glass. This can be attributed to the smoother surface texture.
In spite of the accuracy limits in the measurements of particular elements in glazes, the classification of flux composition into three groups could be confirmed with the p XRF analysis. The measurement precision is therefore sufficient for the semi-quantitative analysis of the flux characteristic of glazes. Especially for the on-site measurement of large sample quantities on historical buildings, the device is a suitable tool.
11.3 Restoration material
The ORMOCER® fulfils the requirements of stability, reversibility, and transparency, which are imposed to a modern restoration material. As pigments, historically coloured glass, cobalt blue, Egyptian blue, lead tin yellow, manganese violet, iron oxide, copper oxide, and cassiterite were used. The metal compounds have higher colour intensities than the pigments of coloured glass. It has to be considered that the proportion of ORMOCER® in the batch must be high enough (70 vol%) to guarantee the ORMOCER® properties of weathering and mechanical stability. The adhesion properties of the ORMOCER® and the homogeneity of the mixture are the best in a fraction of max. 30 vol% particles per ORMOCER®.
With integrated particles, the ORMOCER® G materials show homogeneous coatings, whereas the particles in the ORMCOER® E show more agglomeration. In the sedimentation and weathering experiments, the use of an ultrasonic finger in combination with a roller mill is favourable compared to the treatment with bead grinding mill. The treatments with ultrasonic finger and roller mill result in less sedimentation and better adhesion of the dispersions. The treatment of the dispersions in the bead grinding mill does not result in sufficient adhesion, certainly due to the sedimentation behaviour and a congregation of particles on the bottom of the coating.
The modification of dispersed nano-particles by 3-methacryl-oxypropyltrimethoxysilan leads to a further homogenization in the sedimentation tests. It is therefore approved for the use in coloured glaze supplements. In weathered coatings of nano-particle compounds, the surface modification shows certainly no enhancement of stability.
The treatment of pigmented coatings with an additional layer of pure ORMOCER® results in a bright and transparent appearing, which is closer to the original optical appearance of the glaze. A long-time test application on a historical building will be the next step to validate the suitability of the restoration material.
The natural environment and livelihoods in the Lower Mekong Basin (LMB) are significantly affected by the annual hydrological cycle. Monitoring of soil moisture as a key variable in the hydrological cycle is of great interest in a number of Hydrological and agricultural applications. In this study we evaluated the quality and spatiotemporal variability of the soil moisture product retrieved from C-band scatterometers data across the LMB sub-catchments. The soil moisture retrieval algorithm showed reasonable performance in most areas of the LMB with the exception of a few sub-catchments in the eastern parts of Laos, where the land cover is characterized by dense vegetation. The best performance of the retrieval algorithm was obtained in agricultural regions. Comparison of the available in situ evaporation data in the LMB and the Basin Water Index (BWI), an indicator of the basin soil moisture condition, showed significant negative correlations up to R = −0.85. The inter-annual variation of the calculated BWI was also found corresponding to the reported extreme hydro-meteorological events in the Mekong region. The retrieved soil moisture data show high correlation (up to R = 0.92) with monthly anomalies of precipitation in non-irrigated regions. In general, the seasonal variability of soil moisture in the LMB was well captured by the retrieval method. The results of analysis also showed significant correlation between El Niño events and the monthly BWI anomaly measurements particularly for the month May with the maximum correlation of R = 0.88.
The global-local sustainable development and climate change adaptation policy, and the emerging political discourse on the value of local Adaptation, have positioned the local institutions and their governance space within the strategic enclaves of multilevel governance system. Such shifts have transformed the context for sustainable Nature Based Tourism (NBT) development and adaptation in Nepal in general, and its protected areas, in particular. The emerging institutional adaptation discourse suggests on the need to link tourism development, adaptation and governance within the sustainability concept, and also to recognize the justice and inclusive dimensions of local adaptation. However, sociological investigation of institutional adaptation, particularly at the interface between sustainability, justice and inclusive local adaptation is an undertheorized research topic.
This exploratory study examined the sociological process of the institutional adaptation, especially the social resilience and adaptive governance capacities of the NBT institutions, in 7 Village Development Committees of the Mustang district, a popular destination in the Annapurna Conservation Area, Nepal. Using the sphere (a dynamic social space concept) and quality of governance as the analytical framework, the integrative adaptation as the methodological approach and the case study action research method, the study investigated and generated a holistic picture on the state of the social resilience and adaptive governance capacities of the NBT institutions.
The findings show institutional social resilience capacities to be contingent on socio-political construction of adaptation knowledge and power. Factors influencing such constructions among NBT institutions include: the site and institutions specific political, economic and environmental dispositions; the associated socio-political processes of knowledge constructions and volition action; and the social relationships and interaction, operating within the spheres and at multiple governance levels. The adaptive governance capacities hinge on the institutional arrangements, the procedural aspects of adaptation governance and the governmentality. These are reflective of the diverse legal frameworks, the interiority perspective of the decision making and governance practices of the NBT institutions.
In conclusion, it is argued that effective local adaptation in the Mustang district is contingent on the adaptation and institutional dynamics of the NBT institutions, consisting of the cognitive, subjective, process and procedural aspects of the adaptation knowledge production and its use.
Spatio-Temporal Analysis of Droughts in Semi-Arid Regions by Using Meteorological Drought Indices
(2013)
Six meteorological drought indices including percent of normal (PN), standardized precipitation index (SPI), China-Z index (CZI), modified CZI (MCZI), Z-Score (Z), the aridity index of E. de Martonne (I) are compared and evaluated for assessing spatio-temporal dynamics of droughts in six climatic regions in Iran. Results indicated that by consideration of the advantages and disadvantages of the mentioned drought predictors in Iran, the Z-Score, CZI and MCZI could be used as a good meteorological drought predictor. Depending on the month, the length of drought and climatic conditions of the region, they are an alternative to the SPI that has limitations both because of only a few available long term data series in Iran and its complex structure.
A modified setup featuring high speed high resolution data and video recording was developed to obtain detailed information on trigger and heat transfer times during explosive molten fuel-coolant-interaction (MFCI). MFCI occurs predominantly in configurations where water is entrapped by hot melt. The setup was modified to allow direct observation of the trigger and explosion onset. In addition the influences of experimental control and data acquisition can now be more clearly distinguished from the pure phenomena. More precise experimental studies will facilitate the description of MFCI thermodynamics.
Les sécheresses des années 1970 et 1980 ont occasionné des changements remarquables dans les paysages et écosystèmes sahéliens. Au Niger, les milieux dunaires sont les plus affectés par la dégradation des paysages aux conséquences parfois irréversibles. Cette étude tente de montrer que, malgré les modifications climatiques et les pressions anthropiques, une régénération des sols dunaires serait possible, dans cette dynamique complexe. Cela a été démontré à travers l’analyse micromorphologique des matériaux des parties superficielles des sols (0-20 cm). L’étude des caractéristiques particulières des croûtes (organisations pelliculaires de surface des sols) offre des pistes de recherches pouvant proposer des moyens et méthodes de fixation des dunes dégradées. Elle propose également des alternatives de lutte contre l’érosion éolienne et hydrique dans les écosystèmes sahéliens. Ceci cadre parfaitement avec la situation au Niger, où les phénomènes de désertification et d’ensablement des cuvettes interdunaires constituent une préoccupation majeure en matière de protection de l’environnement.