@article{OttingerBachoferHuthetal.2021, author = {Ottinger, Marco and Bachofer, Felix and Huth, Juliane and Kuenzer, Claudia}, title = {Mapping aquaculture ponds for the coastal zone of Asia with Sentinel-1 and Sentinel-2 time series}, series = {Remote Sensing}, volume = {14}, journal = {Remote Sensing}, number = {1}, issn = {2072-4292}, doi = {10.3390/rs14010153}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-252207}, year = {2021}, abstract = {Asia dominates the world's aquaculture sector, generating almost 90 percent of its total annual global production. Fish, shrimp, and mollusks are mainly farmed in land-based pond aquaculture systems and serve as a primary protein source for millions of people. The total production and area occupied for pond aquaculture has expanded rapidly in coastal regions in Asia since the early 1990s. The growth of aquaculture was mainly boosted by an increasing demand for fish and seafood from a growing world population. The aquaculture sector generates income and employment, contributes to food security, and has become a billion-dollar industry with high socio-economic value, but has also led to severe environmental degradation. In this regard, geospatial information on aquaculture can support the management of this growing food sector for the sustainable development of coastal ecosystems, resources, and human health. With free and open access to the rapidly growing volume of data from the Copernicus Sentinel missions as well as machine learning algorithms and cloud computing services, we extracted coastal aquaculture at a continental scale. We present a multi-sensor approach that utilizes Earth observation time series data for the mapping of pond aquaculture within the entire Asian coastal zone, defined as the onshore area up to 200 km from the coastline. In this research, we developed an object-based framework to detect and extract aquaculture at a single-pond level based on temporal features derived from high-spatial-resolution SAR and optical satellite data acquired from the Sentinel-1 and Sentinel-2 satellites. In a second step, we performed spatial and statistical data analyses of the Earth-observation-derived aquaculture dataset to investigate spatial distribution and identify production hotspots at various administrative units at regional, national, and sub-national scale.}, language = {en} } @phdthesis{Beck2000, author = {Beck, Christoph}, title = {Zirkulationsdynamische Variabilit{\"a}t im Bereich Nordatlantik-Europa seit 1780}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238451}, school = {Universit{\"a}t W{\"u}rzburg}, pages = {350}, year = {2000}, abstract = {In der vorliegenden Studie wurden auf der Basis langer mitteleurop{\"a}ischer Zeitreihen der Temperatur und des Niederschlags sowie rekonstruierter monatlicher Bodenluftdruckfelder f{\"u}r den Bereich Nordatlantik-Europa Untersuchungen zur langperiodischen klimatischen und zirkulationsdynamischen Variabilit{\"a}t im Zeitraum 1780-1995 durchgef{\"u}hrt. Der im Rahmen dieser Arbeit betrachtete Zeitraum umfaßt damit neben dem 20. Jahrhundert, das durch eine zunehmende menschliche Einflußnahme auf das Globalklima gekennzeichnet ist, eine historische, bez{\"u}glich ihrer Klimacharakteristik anthropogen nahezu unbeeinflußte Periode. Vor dem Hintergrund der zeitlichen Limitierung bisheriger zirkulationsdynamischer und synoptisch-klimatologischer Forschungsarbeiten auf die letzten etwa 100 Jahre wurden folgende zentrale Zielsetzungen formuliert: - Erfassung und Darstellung der r{\"a}umlich differenzierten, niederfrequenten thermischen und hygrischen Variabilit{\"a}t in Mitteleuropa seit 1780, auf einer m{\"o}glichst umfassenden und hinsichtlich ihres klimatologischen Aussagewertes optimierten Datenbasis. - Untersuchung der korrespondierenden nordatlantisch-europ{\"a}ischen Zirkulationsver{\"a}nderungen und ihrer Relevanz f{\"u}r die zeitlichen Variationen von Temperatur und Niederschlag in Mitteleuropa. - Analyse der zeitlichen Variabilit{\"a}t der Beziehungen zwischen großr{\"a}umiger atmosph{\"a}rischer Zirkulation und regionalem Klima auf multidekadischer Zeitskala. Ein erster wesentlicher Arbeitsschritt umfaßte die {\"U}berpr{\"u}fung der Homogenit{\"a}t der verf{\"u}gbaren - im Rahmen der Arbeit teilweise wesentlich erweiterten - mitteleurop{\"a}ischen Temperatur- und Niederschlagszeitreihen (72 bzw. 62 Stationsreihen) mittels verschiedener absoluter und relativer Homogenit{\"a}tstests. F{\"u}r einen betr{\"a}chtlichen Teil der Zeitreihen wurden signifikante Inhomogenit{\"a}ten diagnostiziert, die unter Verwendung homogener Referenzreihen homogenisiert werden konnten. Um die angestrebte r{\"a}umlich differenzierte Analyse der klimatischen Ver{\"a}nderungen seit 1780 zu erm{\"o}glichen, erfolgten - basierend auf nichthierarchischen Clusteranalysen der Matrizen der paarweisen Korrelationen zwischen allen Temperatur- bzw. Niederschlagsreihen - objektive Regionalisierungen von Temperatur und Niederschlag. F{\"u}r die resultierenden acht thermischen und neun hygrischen Regionen Mitteleuropas wurden regionale Temperatur- und Niederschlagsreihen berechnet, die bez{\"u}glich ihrer langperiodischen Variabilit{\"a}t analysiert wurden. Im Vordergrund standen dabei die Ermittlung der zeitlichen Abfolge thermischer bzw. hygrischer Anomaliephasen seit 1780 sowie der klimatische Vergleich der sog. fr{\"u}hinstrumentellen Periode (1780-1860) mit einer modernen Referenzperiode (1915-1995). Als wesentliches Ergebnis konnte eine gegen{\"u}ber dem Zeitraum 1780-1860 verminderte kontinentale Pr{\"a}gung des mitteleurop{\"a}ischen Klimas - mit w{\"a}rmeren, feuchteren Wintern und k{\"u}hleren Sommern - in diesem Jahrhundert (1915-1995) festgestellt werden. Als Grundlage f{\"u}r die Analyse der korrespondierenden zirkulationsdynamischen Variabilit{\"a}t wurde eine automatische - hauptkomponenten- und clusteranalytische - Klassifikation rekonstruierter monatlicher nordatlantisch-europ{\"a}ischer Bodenluftdruckfelder erarbeitet. Ein zweiter automatischer Klassifikationsalgorithmus wurde in Anlehnung an die Großwettertypenklassifikation nach Hess/Brezowski unter besonderer Ber{\"u}cksichtigung der Str{\"o}mungsverh{\"a}ltnisse {\"u}ber Europa entwickelt. Die aus den Klassifikationsverfahren resultierenden Druckmusterklassen repr{\"a}sentieren wesentliche Zustandsformen der atmosph{\"a}rischen Zirkulation im nordatlantisch-europ{\"a}ischen Bereich. Basierend auf der Untersuchung der zeitlichen Ver{\"a}nderungen der Auftrittsh{\"a}ufigkeiten der verschiedenen Druckmusterklassen konnten die folgenden wesentlichen Aussagen zur zirkulationsdynamischen Variabilit{\"a}t seit 1780 formuliert werden: - Die zeitliche Entwicklung der Auftrittsh{\"a}ufigkeiten der einzelnen Zirkulationstypen und der daraus aggregierten Zirkulationsformen - zonal, gemischt, meridional - zeigt keine deutlichen langzeitlichen Trends, sondern ist von Schwankungen unterschiedlicher Periodenl{\"a}nge und Amplitude gekennzeichnet. - Einige rezent zu beobachtende Ver{\"a}nderungstendenzen (beispielsweise die Zunahme der winterlichen Zonalzirkulation seit den 1970er Jahren) erscheinen bei Betrachtung des 216-j{\"a}hrigen Gesamtzeitraums als nicht außergew{\"o}hnliche Ereignisse im Rahmen langperiodischer (dekadischer bis s{\"a}kularer) zirkulationsdynamischer Variabilit{\"a}t. Aus dem direkten zirkulationsdynamischen Vergleich der beiden Zeitr{\"a}ume 1780-1860 und 1915-1995 ergeben sich folgende saisonal differenzierte Unterschiede: - In den Wintermonaten Dezember und Januar sind in diesem Jahrhundert deutlich gr{\"o}ßere Auftrittsh{\"a}ufigkeiten von Zirkulationstypen mit s{\"u}dwestlicher bis nordwestlicher Richtungsorientierung des Isobarenverlaufs bei gleichzeitig reduzierten H{\"a}ufigkeiten winterkalter meridionaler Druckmuster festzustellen. Zeitliche Ver{\"a}nderungen umgekehrten Vorzeichens manifestieren sich hingegen im Februar. - Bei intrasaisonal variierenden Befunden im Fr{\"u}hjahr {\"u}berwiegt bei saisonaler Betrachtung eine Zunahme meridionaler Str{\"o}mungskonfigurationen auf Kosten der zonalen und vor allem der gemischten Zirkulationsform. - Im Sommer dominiert eine Abnahme der zonalen Zirkulationsform zugunsten meridionaler Zirkulationstypen, die eine Anstr{\"o}mung aus dem n{\"o}rdlichen Richtungssektor implizieren. - F{\"u}r die Herbstmonate September mit November ergeben sich in diesem Jahrhundert vor allem gesteigerte H{\"a}ufigkeiten von Str{\"o}mungskonfigurationen, die die Heranf{\"u}hrung von Luftmassen aus westlichen bis nordwestlichen Richtungen bedingen. - Eine m{\"o}glicherweise grundlegende Modifikation der nordatlantisch-europ{\"a}ischen Zirkulation in diesem Jahrhundert deutet sich bez{\"u}glich des h{\"a}ufigeren Wechsels zwischen stark zonal bzw. meridional gepr{\"a}gten Phasen - vor allem im Winter - an. Mittels eines einfachen empirischen Modellansatzes wurde anschließend analysiert, inwieweit sich die diagnostizierten klimatischen Unterschiede zwischen den beiden Zeitr{\"a}umen 1780-1860 und 1915-1995 aus den festgestellten zeitlichen Ver{\"a}nderungen der Zirkulationsstrukturen ergeben. Es wurde deutlich, daß nur ein Teil der Temperatur- und Niederschlagsver{\"a}nderungen zwischen historischem Zeitraum und diesem Jahrhundert durch differierende Auftrittsh{\"a}ufigkeiten witterungsklimatisch homogener Zirkulationstypen erkl{\"a}rt werden kann. Ein betr{\"a}chtlicher Anteil der klimatischen Unterschiedlichkeiten der beiden Vergleichszeitr{\"a}ume ist offensichtlich auf zeitlich variierende Witterungscharakteristika der einzelnen Str{\"o}mungskonfigurationen („within-type changes" - zirkulationstypinterne Ver{\"a}nderungen) zur{\"u}ckzuf{\"u}hren. Das Ausmaß der typinternen klimatischen Modifikationen konnte durch die Berechnung der in den beiden Vergleichszeitr{\"a}umen ausgebildeten typspezifischen mittleren Temperatur- und Niederschlagsverh{\"a}ltnisse quantifiziert werden. Die Fraktionierung der zirkulationstypspezifischen Temperatur- bzw. Niederschlags{\"a}nderungsbetr{\"a}ge in einen durch variierende Auftrittsh{\"a}ufigkeiten bedingten sowie einen auf typinterne Ver{\"a}nderungen zur{\"u}ckzuf{\"u}hrenden Anteil belegt, daß in allen Jahreszeiten internen klimatischen Modifikationen der Zirkulationstypen mit s{\"u}dwestlicher bis nordwestlicher Isobarenverlaufsrichtung eine gewichtige Rolle bei der Generierung zeitlicher Unterschiede der mitteleurop{\"a}ischen Temperatur- und Niederschlagscharakteristik zukommt. Als Ursache der zirkulationstypinternen Ver{\"a}nderungen konnten zum einen unterschiedliche Ausgestaltungen der typspezifischen Druckmuster im historischen und im rezenten Zeitraum identifiziert werden (beispielsweise zeitlich variierende Druckgradienten bei generell {\"u}bereinstimmenden Str{\"o}mungskonfigurationen), zum anderen deuten sich auf der t{\"a}glichen Zeitskala Ver{\"a}nderungen der Persistenzen einzelner Zirkulationstypen an. Diese zirkulationsdynamischen Modifikationen stellen aber nicht in allen F{\"a}llen einen hinreichenden Erkl{\"a}rungsansatz f{\"u}r die diagnostizierten „within-type changes" dar, so daß zus{\"a}tzlich andere verursachende Faktorenkomplexe in Betracht gezogen werden m{\"u}ssen (beispielsweise modifizierte thermische und hygrische Luftmasseneigenschaften aufgrund ver{\"a}nderter Energiefl{\"u}sse zwischen Ozean und Atmosph{\"a}re). Mit Blick auf diese Resultate wurden die Beziehungen zwischen großr{\"a}umiger Zirkulation und regionalem bodennahem Klima mittels kanonischer Korrelationsanalysen monatlicher Bodenluftdruckfelder und regionaler mitteleurop{\"a}ischer Temperatur- und Niederschlagszeitreihen detaillierter hinsichtlich ihrer zeitlichen Variabilit{\"a}t untersucht. Die wesentlichen Ergebnisse lassen sich wie folgt zusammenfassen: - In allen Jahreszeiten zeigen sich im Zeitraum 1780-1995 ausgepr{\"a}gte zeitliche Schwankungen des statistisch beschreibbaren Zusammenhangs zwischen großr{\"a}umiger atmosph{\"a}rischer Zirkulation und regionalem Klima (Temperatur und Niederschlag in Mitteleuropa). - Ein Vergleich der beiden Perioden 1780-1860 und 1915-1995 hinsichtlich der Kopplungsmechanismen zwischen Bodenluftdruckverteilung und Klima ergibt teilweise hochsignifikante Unterschiede. - Die Modellierung von Temperatur und Niederschlag in Mitteleuropa aus monatlichen Druckfeldern jeweils einem der Zeitabschnitte 1780-1860 und 1915-1995 unter Verwendung der im jeweils anderen Zeitraum etablierten statistischen Zusammenh{\"a}nge erbringt nur in einem Fall (Januartemperaturen) befriedigende {\"U}bereinstimmungen zwischen den modellierten und beobachteten Klimaverh{\"a}ltnissen. Die in dieser Arbeit vorgestellten Untersuchungsergebnisse lassen die Schlußfolgerung zu, daß sich die im 20. Jahrhundert zu verzeichnenden Zirkulationsver{\"a}nderungen im nordatlantisch-europ{\"a}ischen Sektor bislang noch in das Spektrum nat{\"u}rlicher zirkulationsdynamischer Variabilit{\"a}t einf{\"u}gen. Diese Aussage stellt aber weder die wahrscheinliche Mitwirkung des anthropogen verst{\"a}rkten Treibhauseffekts an den in diesem Jahrhundert beobachteten Zirkulationsdynamischen Entwicklungen im euro-atlantischen Bereich in Frage, noch kann sie als Argument f{\"u}r die Aufschiebung notwendiger klimapolitischer Entscheidungen oder f{\"u}r die verz{\"o}gerte Entwicklung und Umsetzung von Handlungsstrategien zur wirksamen Reduzierung klimawirksamer Treibhausgasemissionen aufgefaßt werden.}, subject = {Europa}, language = {de} } @phdthesis{NghengwaAche2019, author = {Nghengwa Ache, Patience}, title = {Waste Management As a Correlate of Environmental Sustainability in Sub-Saharan Africa: The Example of Imo State, Nigeria}, doi = {10.25972/OPUS-19224}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-192240}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Summary Introduction. Rapid and uncontrolled industrialisation and urbanisation in most developing countries are resulting in land, air and water pollution at rates that the natural environment cannot fully renew. These contemporary environmental issues have attracted local, national and international attention. The problem of urban garbage management is associated with rapid population growth in developing countries. These are pertinent environmental crises of sustainability and sanitation in Sub-Saharan Africa and other Third World countries. Despite efforts of the various tiers of government (the case of Nigeria with three tiers: Federal, State and Local governments) in managing solid waste in urban centres, it is still overflowing open dumpsites, litters streets and encroaches into water bodies. These affect the quality of urban living conditions and the natural environment. Sub-Saharan and other developing countries are experiencing an upsurge in the accumulation and the diversity of waste including E-waste, waste agricultural biomass and waste plastics. The need for effective, sustainable and efficient management of waste through the application of 3Rs principle (Reduce, Reuse, and Recycle) is an essential element for promoting sustainable patterns of consumption and production. This study examined waste management in Imo State, Nigeria as an aspect correlated to the sustainability of its environment. Materials and methods. To analyse waste management as a correlate of environmental sustainability in Sub-Saharan Africa, Imo State, in eastern Nigeria was chosen as a study area. Issues about waste handling and its impact on the environment in Imo have been reported since its creation in 1976; passing through the State with the cleanest State capital in 1980 to a 'dunghill' in 2013 and a 'garbage capital' on October 1, 2016. Within this State, three study sites were selected - Owerri metropolis (the State capital) Orlu and Okigwe towns. At these sites, households, commercial areas, accommodation and recreational establishments and schools, as well as dumpsites were investigated to ascertain the composition, quantity, distribution, handling patterns of waste in relation to the sustainability of the State's environment. This was done conveniently but randomly through questionnaires, interviews, focus group discussions and non-participant observation; these were all heralded by a detailed deskwork. Data were entered using Microsoft Office Excel and were explored and analysed using the Statistical Package for Social Sciences - SPSS. Data were made essentially of categorical variables and were analysed using descriptive statistics. The association between categorical variables was measured using Cramer's V the Chi-Square that makes the power and the reliability of the test. Cramer's V is a measure of association tests directly integrated with cross-tabulation. The Chi-Square test of equal proportions was used to compare proportions for significant differences at 0.05 levels. The statistical package - the Epi Info 6.04d was also used since a contingency table had to be created from several sub-outputs and determine the extent of association between the row and column categories. The scale variable 'quantity of waste generated' was described using measures of central tendency. It was screened for normality using the Kolmogorov-Smirnov and Shapiro-Wilk tests for normality; in all context, the normality assumption was violated (P<0.05). Five null hypotheses were tested using Logistic Regression model. The explanatory power of individual conceptual component was calculated using the Cox \& Snell R2 and that of individual indicators was also appraised using the Likelihood Ratio test. In the context of this work, the significance of the variability explained by the model (baseline model) was appraised using the Omnibus Tests of Model Coefficients, the magnitude of this variability explained by the model using the Cox \& Snell R2 and the effects of individual predictors using the Likelihood Ratio test. Qualitatively, data from open-ended items, observations and interviews were analysed using the process of thematic analysis whereby concepts or ideas were grouped under umbrella terms or keywords. The results were presented using tables, charts, graphs, photos and maps. Findings and discussions. The total findings and analyses indicated that proper waste handling in Imo State, Nigeria has a positive impact on the environment. This was assessed by the community's awareness of waste management via sources like the radio and the TV, their education on waste management and schools' integration of environmental education in their program. Although most community members perceived the State's environment as compared to it about 10 years' back has worsened, where they were conscious of proper waste handling measures, the environment was described to be better. This influence of environmental awareness and education on environmental sustainability appraised using Logistic Regression Model, portrayed a significant variability (Omnibus Tests of Model Coefficients: χ2=42.742; P=0.014), inferring that environmental awareness and education significantly predict environmental sustainability. The findings also revealed that organic waste generation spearheaded amongst other waste types like paper, plastic, E-waste, metal, textile and glass. While waste pickers always sorted paper, plastics, aluminium and metal, some of them also sorted out textile and glass. Statistically (P<0.05), in situations where waste was least generated (i.e., 1-2kg per day), community members maintained that the environmental quality was better in comparison to 10 years' back. Waste items like broken glass and textile as well as the remains of E-waste after the extraction of copper and brass were not sorted for and these contributed more to environmental degradation. Similarly, the influence of wealth on environmental sustainability was appraised using Logistic Regression Model including development index related indicators like education, occupation, income and the ability to pay for waste disposal. Harmonising the outcome, farmers, who were mostly the least educated claimed to notice more environmental improvement. In addition, those who did not agree to pay for waste disposal who were mostly those with low income (less than 200,000 Naira, i.e. about 620 Euros monthly) perceived environmental improvement more than those with income above 200,000 Naira. This irony can be attributed to the fact that those with low educational backing lack the capacity to appreciate environmental sustainability pointers well as compared to those with a broader educational background with critical thinking. The employment and poverty reduction opportunities pertaining to waste management on environmental sustainability was appraised using qualitative thematic analysis. All community members involved in sorting, buying and selling of waste items had no second job. They attested that the money earned from their activities sustained their livelihood and families. Some expressed love for the job, especially as they were their own masters. Waste picking and trading in waste items are offering employment opportunities to many communities around the world. For instance, in the waste recycling, waste composting, waste-to-energy plants and die Stadtreiniger in W{\"u}rzburg city. The workers in these enterprises have jobs as a result of waste. Waste disposal influence on environmental sustainability was appraised using the Binary Logistic Regression Model and the variability explained by the model was significant. The validity was also supported by the Wald statistics (P<0.05), which indicates the effect of the predictors is significant. Environmental sustainability was greatly reliant on indicators like the frequency at which community members emptied their waste containers; how/where waste is disposed of, availability of disposal site or public bin near the house, etc. Imolites who asserted to have public waste bins or disposal sites near their houses maintained that the quality of the State's environment had worsened as such containers/disposal sites were always stinking as well as had animals and smoke around them. Imolites around disposal sites complained of traits like diarrhoea, catarrh, insect bites, malaria, smoke and polluted air. Conclusions. The liaison between poor waste management strategies and the sustainability of the Imo State environment was considered likely as statistically significant ineffectiveness, lack of awareness, poverty, insufficient and unrealistic waste management measures were found in this study area. In these situations, the environment was said to have not improved. Such inadequacies in the handling of generated waste did not only expose the citizenry to health dangers but also gave rise to streets and roads characterized by filth and many unattended disposal sites unleashing horrible odour to the environment and attracting wild animals. This situation is not only prevalent in Imo State, Nigeria but in many Sub-Saharan cities. Future Perspectives. To improve the environment in Sub-Saharan Africa, it is imperative to practice an inclusive and integrated sustainable waste management system. The waste quantity in this region is fast growing, especially food/organic waste. The region should aim at waste management laws and waste reduction strategies, which will help save and produce more food that it really needs. Waste management should be dissociated from epidemic outbreaks like cholera, typhoid, Lassa fever and malaria, whose vectors thrive in filthy environments. Water channels and water bodies should not be waste disposal channels or waste disposal sites.}, language = {en} } @phdthesis{Emmert2020, author = {Emmert, Adrian Alexander}, title = {The Internal Structure of Periglacial Landforms - Assessments of Subsurface Variations in Permafrost-related and Frost-related Phenomena by Multi-dimensional Geophysical Investigations}, edition = {1. Auflage}, publisher = {W{\"u}rzburg University Press}, address = {W{\"u}rzburg}, isbn = {978-3-95826-138-9}, doi = {10.25972/WUP-978-3-95826-139-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202437}, school = {W{\"u}rzburg University Press}, pages = {xix, 167}, year = {2020}, abstract = {The internal structure of periglacial landforms contains valuable information on past and present environmental conditions. To benefit from this archive, however, an enhanced understanding of subsurface variations is crucial. This enables to assess the influence of the internal structure on prevailing process regimes and to evaluate the sensitivity of different landform units to environmental changes. This thesis investigates structural variations in the subsurface of (i) rock glaciers,(ii) solifluction lobes, (iii) palsas/ lithalsas and (iv) patterned ground, which occur between the different landform types, but also between landform units of the same type. Investigated variables comprise (i) the spatial distribution of permafrost, (ii) ground ice content, (iii) the origin of ground ice, (iv) thickness of the active layer and (v) frost table topography. Multi-dimensional investigations by the geophysical methods Electrical Resistivity Imaging (ERI) and Ground-Penetrating Radar (GPR) were performed in six study areas (a-f): four of them are located in high-alpine environments in Switzerland and two of them are located in the subarctic highlands of Iceland. Additionally, surface and subsurface temperature values were continuously recorded at selected study sites. At one study site, pF-values, representing the matric potential (or water potential), were recorded. From a methodological view, this thesis focuses on the application of quasi-3-D ERI, an approach in which many two-dimensional data sets are combined to create one three-dimensional data set. This permits e.g., a three-dimensional delimitation of subsurface structures and a spatial investigation of the distribution of ground ice. Besides the analysis of field data, this thesis incudes a comparison between inversion models produced with different software products, based on two synthetic data sets. The detection of resistivity structures and reflection patterns provides valuable insights into the internal structure of the investigated landform units: At the high-alpine study site at (a) Piz Nair, a highly variable ice content indicates a complex development of the investigated rock glacier assembly. The local formation of ground ice is attributed to an embedding of surface patches of snow or ice into the subsurface by rockfall. Results of geoelectric monitoring surveys on selected rock glaciers show the influence of seasonal alterations in the internal structure on subsurface meltwater flow. At the study site at (b) Piz {\"U}ertsch, results indicate the occurrences of isolated ground ice patches in a significantly larger rock glacier. Detected characteristics of the internal structure enable to reconstruct the development of the rock glacier, in which a temporary override of an adjacent glacier tongue on the rock glacier is considered crucial for the current distribution of ground ice. However, results of this thesis clearly show the absence of buried glacier ice in the subsurface of the rock glacier. Results from a rock glacier near the (c) Las Trais Fluors mountain ridge affirm the existence of a water-permeable frozen layer, which was assumed in previous studies. Furthermore, results show that the rock glacier contains large amounts of rockfall deposits. A joint interpretation of ERI and GPR results from the investigated scree slope at the mountain (d) Blauberg (Furka Pass) reveals characteristic structures in the subsurface, which enable a differentiation between solifluction lobes and pebbly rock glaciers. At the subarctic study site (e) Orravatnsr{\´u}stir, results show that the internal structure of palsas can be used to deduce their current development stage and to assess past and future developments. Presented results affirm a long history of palsa development at the study site, as assumed in previous studies, but indicate recently changing environmental conditions. The investigated occurrences of patterned ground in the proglacial area of the glacier (f) Hofsj{\"o}kull are currently not influenced by the detected occurrence of permafrost, according to the presented results. Therefore, a temporary formation of pattered ground is assumed, which is linked to the retreat of the glacier. This thesis shows discrepancies between the internal structure of some of the investigated landform units and the recent environmental conditions. This indicates a delayed adaption and a low sensitivity of the landform units to environmental changes. Findings indicate that the future development of permafrost will be strongly affected by variations in snowfall. Furthermore, the detection of isolated occurrences of ground ice at several study sites contradicts the widely assumed effectivity of balancing heat fluxes to create homogenous subsurface conditions in relatively fine-grained subsurface materials.}, subject = {Permafrost}, language = {en} } @article{RoeschPlank2022, author = {R{\"o}sch, Moritz and Plank, Simon}, title = {Detailed mapping of lava and ash deposits at Indonesian volcanoes by means of VHR PlanetScope change detection}, series = {Remote Sensing}, volume = {14}, journal = {Remote Sensing}, number = {5}, issn = {2072-4292}, doi = {10.3390/rs14051168}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-262232}, year = {2022}, abstract = {Mapping of lava flows in unvegetated areas of active volcanoes using optical satellite data is challenging due to spectral similarities of volcanic deposits and the surrounding background. Using very high-resolution PlanetScope data, this study introduces a novel object-oriented classification approach for mapping lava flows in both vegetated and unvegetated areas during several eruptive phases of three Indonesian volcanoes (Karangetang 2018/2019, Agung 2017, Krakatau 2018/2019). For this, change detection analysis based on PlanetScope imagery for mapping loss of vegetation due to volcanic activity (e.g., lava flows) is combined with the analysis of changes in texture and brightness, with hydrological runoff modelling and with analysis of thermal anomalies derived from Sentinel-2 or Landsat-8. Qualitative comparison of the mapped lava flows showed good agreement with multispectral false color time series (Sentinel-2 and Landsat-8). Reports of the Global Volcanism Program support the findings, indicating the developed lava mapping approach produces valuable results for monitoring volcanic hazards. Despite the lack of bands in infrared wavelengths, PlanetScope proves beneficial for the assessment of risk and near-real-time monitoring of active volcanoes due to its high spatial (3 m) and temporal resolution (mapping of all subaerial volcanoes on a daily basis).}, language = {en} } @article{RoesslerWittIkonenetal.2021, author = {R{\"o}ßler, Sebastian and Witt, Marius S. and Ikonen, Jaakko and Brown, Ian A. and Dietz, Andreas J.}, title = {Remote sensing of snow cover variability and its influence on the runoff of S{\´a}pmi's rivers}, series = {Geosciences}, volume = {11}, journal = {Geosciences}, number = {3}, issn = {2076-3263}, doi = {10.3390/geosciences11030130}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-234261}, year = {2021}, abstract = {The boreal winter 2019/2020 was very irregular in Europe. While there was very little snow in Central Europe, the opposite was the case in northern Fenno-Scandia, particularly in the Arctic. The snow cover was more persistent here and its rapid melting led to flooding in many places. Since the last severe spring floods occurred in the region in 2018, this raises the question of whether more frequent occurrences can be expected in the future. To assess the variability of snowmelt related flooding we used snow cover maps (derived from the DLR's Global SnowPack MODIS snow product) and freely available data on runoff, precipitation, and air temperature in eight unregulated river catchment areas. A trend analysis (Mann-Kendall test) was carried out to assess the development of the parameters, and the interdependencies of the parameters were examined with a correlation analysis. Finally, a simple snowmelt runoff model was tested for its applicability to this region. We noticed an extraordinary variability in the duration of snow cover. If this extends well into spring, rapid air temperature increases leads to enhanced thawing. According to the last flood years 2005, 2010, 2018, and 2020, we were able to differentiate between four synoptic flood types based on their special hydrometeorological and snow situation and simulate them with the snowmelt runoff model (SRM).}, language = {en} } @article{DobińskiKneisel2021, author = {Dobiński, Wojciech and Kneisel, Christof}, title = {Permafrost and glaciers: perspectives for the Earth and planetary sciences — another step forward}, series = {Geosciences}, volume = {11}, journal = {Geosciences}, number = {2}, issn = {2076-3263}, doi = {10.3390/geosciences11020068}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228766}, year = {2021}, abstract = {No abstract available}, language = {en} } @article{RemelgadoSafiWegmann2020, author = {Remelgado, Ruben and Safi, Kamran and Wegmann, Martin}, title = {From ecology to remote sensing: using animals to map land cover}, series = {Remote Sensing in Ecology and Conservation}, volume = {6}, journal = {Remote Sensing in Ecology and Conservation}, number = {1}, doi = {10.1002/rse2.126}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225200}, pages = {93-104}, year = {2020}, abstract = {Land cover is a key variable in monitoring applications and new processing technologies made deriving this information easier. Yet, classification algorithms remain dependent on samples collected on the field and field campaigns are limited by financial, infrastructural and political boundaries. Here, animal tracking data could be an asset. Looking at the land cover dependencies of animal behaviour, we can obtain land cover samples over places that are difficult to access. Following this premise, we evaluated the potential of animal movement data to map land cover. Specifically, we used 13 White Storks (Cicona cicona) individuals of the same population to map agriculture within three test regions distributed along their migratory track. The White Stork has adapted to foraging over agricultural lands, making it an ideal source of samples to map this land use. We applied a presence-absence modelling approach over a Normalized Difference Vegetation Index (NDVI) time series and validated our classifications, with high-resolution land cover information. Our results suggest White Stork movement is useful to map agriculture, however, we identified some limitations. We achieved high accuracies (F1-scores > 0.8) for two test regions, but observed poor results over one region. This can be explained by differences in land management practices. The animals preferred agriculture in every test region, but our data showed a biased distribution of training samples between irrigated and non-irrigated land. When both options occurred, the animals disregarded non-irrigated land leading to its misclassification as non-agriculture. Additionally, we found difference between the GPS observation dates and the harvest times for non-irrigated crops. Given the White Stork takes advantage of managed land to search for prey, the inactivity of these fields was the likely culprit of their underrepresentation. Including more species attracted to agriculture - with other land-use dependencies and observation times - can contribute to better results in similar applications.}, language = {en} } @article{ArendtReinhardtImjelaSchulteetal.2021, author = {Arendt, Robert and Reinhardt-Imjela, Christian and Schulte, Achim and Faulstich, Leona and Ullmann, Tobias and Beck, Lorenz and Martinis, Sandro and Johannes, Petrina and Lengricht, Joachim}, title = {Natural pans as an important surface water resource in the Cuvelai Basin — Metrics for storage volume calculations and identification of potential augmentation sites}, series = {Water}, volume = {13}, journal = {Water}, number = {2}, issn = {2073-4441}, doi = {10.3390/w13020177}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-223019}, year = {2021}, abstract = {Numerous ephemeral rivers and thousands of natural pans characterize the transboundary Iishana-System of the Cuvelai Basin between Namibia and Angola. After the rainy season, surface water stored in pans is often the only affordable water source for many people in rural areas. High inter- and intra-annual rainfall variations in this semiarid environment provoke years of extreme flood events and long periods of droughts. Thus, the issue of water availability is playing an increasingly important role in one of the most densely populated and fastest growing regions in southwestern Africa. Currently, there is no transnational approach to quantifying the potential storage and supply functions of the Iishana-System. To bridge these knowledge gaps and to increase the resilience of the local people's livelihood, suitable pans for expansion as intermediate storage were identified and their metrics determined. Therefore, a modified Blue Spot Analysis was performed, based on the high-resolution TanDEM-X digital elevation model. Further, surface area-volume ratio calculations were accomplished for finding suitable augmentation sites in a first step. The potential water storage volume of more than 190,000 pans was calculated at 1.9 km\(^3\). Over 2200 pans were identified for potential expansion to facilitate increased water supply and flood protection in the future.}, language = {en} } @phdthesis{Dirscherl2022, author = {Dirscherl, Mariel Christina}, title = {Remote Sensing of Supraglacial Lake Dynamics in Antarctica - Exploiting Methods from Artificial Intelligence for Derivation of Antarctic Supraglacial Lake Extents in Multi-Sensor Remote Sensing Data}, doi = {10.25972/OPUS-27950}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-279505}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {With accelerating global climate change, the Antarctic Ice Sheet is exposed to increasing ice dynamic change. During 1992 and 2017, Antarctica contributed ~7.6 mm to global sea-level-rise mainly due to ocean thermal forcing along West Antarctica and atmospheric warming along the Antarctic Peninsula (API). Together, these processes caused the progressive retreat of glaciers and ice shelves and weakened their efficient buttressing force causing widespread ice flow accelerations. Holding ~91\% of the global ice mass and 57.3 m of sea-level-equivalent, the Antarctic Ice Sheet is by far the largest potential contributor to future sea-level-rise. Despite the improved understanding of Antarctic ice dynamics, the future of Antarctica remains difficult to predict with its contribution to global sea-level-rise representing the largest uncertainty in current projections. Given that recent studies point towards atmospheric warming and melt intensification to become a dominant driver for future Antarctic ice mass loss, the monitoring of supraglacial lakes and their impacts on ice dynamics is of utmost importance. In this regard, recent progress in Earth Observation provides an abundance of high-resolution optical and Synthetic Aperture Radar (SAR) satellite data at unprecedented spatial and temporal coverage and greatly supports the monitoring of the Antarctic continent where ground-based mapping efforts are difficult to perform. As an automated mapping technique for supraglacial lake extent delineation in optical and SAR satellite imagery as well as a pan-Antarctic inventory of Antarctic supraglacial lakes at high spatial and temporal resolution is entirely missing, this thesis aims to advance the understanding of Antarctic surface hydrology through exploitation of spaceborne remote sensing. In particular, a detailed literature review on spaceborne remote sensing of Antarctic supraglacial lakes identified several research gaps including the lack of (1) an automated mapping technique for optical or SAR satellite data that is transferable in space and time, (2) high-resolution supraglacial lake extent mappings at intra-annual and inter-annual temporal resolution and (3) large-scale mapping efforts across the entire Antarctic continent. In addition, past method developments were found to be restricted to purely visual, manual or semi-automated mapping techniques hindering their application to multi-temporal satellite imagery at large-scale. In this context, the development of automated mapping techniques was mainly limited by sensor-specific characteristics including the similar appearance of supraglacial lakes and other ice sheet surface features in optical or SAR data, the varying temporal signature of supraglacial lakes throughout the year as well as effects such as speckle noise and wind roughening in SAR data or cloud coverage in optical data. To overcome these limitations, this thesis exploits methods from artificial intelligence and big data processing for development of an automated processing chain for supraglacial lake extent delineation in Sentinel-1 SAR and optical Sentinel-2 satellite imagery. The combination of both sensor types enabled to capture both surface and subsurface lakes as well as to acquire data during cloud cover or wind roughening of lakes. For Sentinel-1, a deep convolutional neural network based on residual U-Net was trained on the basis of 21,200 labeled Sentinel-1 SAR image patches covering 13 Antarctic regions. Similarly, optical Sentinel-2 data were collected over 14 Antarctic regions and used for training of a Random Forest classifier. Optical and SAR classification products were combined through decision-level fusion at bi-weekly temporal scale and unprecedented 10 m spatial resolution. Finally, the method was implemented as part of DLR's High-Performance Computing infrastructure allowing for an automated processing of large amounts of data including all required pre- and postprocessing steps. The results of an accuracy assessment over independent test scenes highlighted the functionality of the classifiers returning accuracies of 93\% and 95\% for supraglacial lakes in Sentinel-1 and Sentinel-2 satellite imagery, respectively. Exploiting the full archive of Sentinel-1 and Sentinel-2, the developed framework for the first time enabled the monitoring of seasonal characteristics of Antarctic supraglacial lakes over six major ice shelves in 2015-2021. In particular, the results for API ice shelves revealed low lake coverage during 2015-2018 and particularly high lake coverage during the 2019-2020 and 2020-2021 melting seasons. On the contrary, East Antarctic ice shelves were characterized by high lake coverage during 2016-2019 and extremely low lake coverage during the 2020-2021 melting season. Over all six investigated ice shelves, the development of drainage systems was revealed highlighting an increased risk for ice shelf instability. Through statistical correlation analysis with climate data at varying time lags as well as annual data on Southern Hemisphere atmospheric modes, environmental drivers for meltwater ponding were revealed. In addition, the influence of the local glaciological setting was investigated through computation of annual recurrence times of lakes. Over both ice sheet regions, the complex interplay between local, regional and large-scale environmental drivers was found to control supraglacial lake formation despite local to regional discrepancies, as revealed through pixel-based correlation analysis. Local control factors included the ice surface topography, the ice shelf geometry, the presence of low-albedo features as well as a reduced firn air content and were found to exert strong control on lake distribution. On the other hand, regional controls on lake evolution were revealed to be the amount of incoming solar radiation, air temperature and wind occurrence. While foehn winds were found to dictate lake evolution over the API, katabatic winds influenced lake ponding in East Antarctica. Furthermore, the regional near-surface climate was shown to be driven by large-scale atmospheric modes and teleconnections with the tropics. Overall, the results highlight that similar driving factors control supraglacial lake formation on the API and EAIS pointing towards their transferability to other Antarctic regions.}, subject = {Optische Fernerkundung}, language = {en} } @article{MeisterGarbeTrappeetal.2021, author = {Meister, Julia and Garbe, Philipp and Trappe, Julian and Ullmann, Tobias and Es-Senussi, Ashraf and Baumhauer, Roland and Lange-Athinodorou, Eva and El-Raouf, Amr Abd}, title = {The Sacred Waterscape of the Temple of Bastet at Ancient Bubastis, Nile Delta (Egypt)}, series = {Geosciences}, volume = {11}, journal = {Geosciences}, number = {9}, issn = {2076-3263}, doi = {10.3390/geosciences11090385}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246129}, year = {2021}, abstract = {Sacred water canals or lakes, which provided water for all kinds of purification rites and other activities, were very specific and important features of temples in ancient Egypt. In addition to the longer-known textual record, preliminary geoarchaeological surveys have recently provided evidence of a sacred canal at the Temple of Bastet at Bubastis. In order to further explore the location, shape, and course of this canal and to find evidence of the existence of a second waterway, also described by Herodotus, 34 drillings and five 2D geoelectrical measurements were carried out in 2019 and 2020 near the temple. The drillings and 2D ERT surveying revealed loamy to clayey deposits with a thickness of up to five meters, most likely deposited in a very low energy fluvial system (i.e., a canal), allowing the reconstruction of two separate sacred canals both north and south of the Temple of Bastet. In addition to the course of the canals, the width of about 30 m fits Herodotus' description of the sacred waterways. The presence of numerous artefacts proved the anthropogenic use of the ancient canals, which were presumably connected to the Nile via a tributary or canal located west or northwest of Bubastis.}, language = {en} } @phdthesis{Blaettler1995, author = {Bl{\"a}ttler, Regine}, title = {Rezente fluviale Morphodynamik im Stubaital, Tirol}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-239248}, school = {Universit{\"a}t W{\"u}rzburg}, year = {1995}, abstract = {Andauernde Starkniederschl{\"a}ge f{\"u}hrten 1987 in zahlreichen Alpent{\"a}lem zu schweren Hochwasser- und Murkatastrophen. Auch das von der Ruetz entw{\"a}sserte Tiroler Stubaital s{\"u}dwestlich Innsbruck z{\"a}hlte zu den betroffenen T{\"a}lern. Im Abstand von nur sechs Wochen verursachten hier zwei Hochwasserereignisse {\"a}hnlichen Ausmaßes schwere Verw{\"u}stungen und Landschaftssch{\"a}den. Die Auswirkungen beider Hochw{\"a}sser bildeten die Ansatzpunkte der als Teilprojekt Stubai von Mitte 1988 bis Ende 1991 im Stubaital und einem seiner Seitent{\"a}ler laufenden Forschungsarbeit. Das Hauptinteresse galt dabei, nach Abschluß einer ausf{\"u}hrlichen Schadenskartierung und Photodokumentation, den Ursachen, Zusammenh{\"a}ngen und Auswirkungen einzelner morphodynamisch wirksamer Prozesse. Verschiedene Felduntersuchungen in einem Seitental des Stubaitales gaben hinsichtlich des Zusammenspiels von Abfluß, Niederschlag, Hangabtrag und Vegetation Aufschluß dar{\"u}ber, wann, wie und in welchem Zeitraum einzelne morphodynamisch wirksame Prozesse im Bachbett bzw. im Kontaktbereich Hang/Bach ablaufen. Um Aussagen dar{\"u}ber machen zu k{\"o}nnen, inwieweit das Hochwassersedimentationsverhalten der Ruetz innerhalb der letzten Jahrhunderte klimatisch beeinflußt wurde, und ob die touristische Erschließung des hinteren Stubaitales das Hochwasserabflußgeschehen der Ruetz in Bezug auf H{\"a}ufigkeit und Intensit{\"a}t in den letzten Jahren erkennbar beeinflußte, wurden im Auebereich der Ruetz mehrere Schlitzsonden- und Kernbohrungen abgeteuft. Die Auswertung der Bohrkeme und verschiedene Laboranalysen des gewonnenen Probenmaterials gaben einerseits Auskunft {\"u}ber Zusammensetzung, M{\"a}chtigkeit und Herkunft einzelner Hochwasserablagerungen, andererseits konnten anhand dieser Aussagen das fr{\"u}here Akkumulationsverhalten und verschiedene Laufverlagerungen der Ruetz f{\"u}r diesen Auebereich rekonstruiert werden. Ebenso konnte der direkte Einfluß des Menschen auf das Hochwassersed imentationsgeschehen und somit die anthropogene Beeinflussung der Hochflut-/Auedynamik bereits f{\"u}r historische Zeit festgestellt und belegt werden.}, subject = {Stubai}, language = {de} } @article{UsmanReimannLiedletal.2018, author = {Usman, Muhammad and Reimann, Thomas and Liedl, Rudolf and Abbas, Azhar and Conrad, Christopher and Saleem, Shoaib}, title = {Inverse parametrization of a regional groundwater flow model with the aid of modelling and GIS: test and application of different approaches}, series = {ISPRS International Journal of Geo-Information}, volume = {7}, journal = {ISPRS International Journal of Geo-Information}, number = {1}, doi = {10.3390/ijgi7010022}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175721}, pages = {22}, year = {2018}, abstract = {The use of inverse methods allow efficient model calibration. This study employs PEST to calibrate a large catchment scale transient flow model. Results are demonstrated by comparing manually calibrated approaches with the automated approach. An advanced Tikhonov regularization algorithm was employed for carrying out the automated pilot point (PP) method. The results indicate that automated PP is more flexible and robust as compared to other approaches. Different statistical indicators show that this method yields reliable calibration as values of coefficient of determination (R-2) range from 0.98 to 0.99, Nash Sutcliffe efficiency (ME) range from 0.964 to 0.976, and root mean square errors (RMSE) range from 1.68 m to 1.23 m, for manual and automated approaches, respectively. Validation results of automated PP show ME as 0.969 and RMSE as 1.31 m. The results of output sensitivity suggest that hydraulic conductivity is a more influential parameter. Considering the limitations of the current study, it is recommended to perform global sensitivity and linear uncertainty analysis for the better estimation of the modelling results.}, language = {en} } @article{ZieglerPollingerBoelletal.2020, author = {Ziegler, Katrin and Pollinger, Felix and B{\"o}ll, Susanne and Paeth, Heiko}, title = {Statistical modeling of phenology in Bavaria based on past and future meteorological information}, series = {Theoretical and Applied Climatology}, volume = {140}, journal = {Theoretical and Applied Climatology}, issn = {0177-798X}, doi = {10.1007/s00704-020-03178-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232717}, pages = {1467-1481}, year = {2020}, abstract = {Plant phenology is well known to be affected by meteorology. Observed changes in the occurrence of phenological phases arecommonly considered some of the most obvious effects of climate change. However, current climate models lack a representationof vegetation suitable for studying future changes in phenology itself. This study presents a statistical-dynamical modelingapproach for Bavaria in southern Germany, using over 13,000 paired samples of phenological and meteorological data foranalyses and climate change scenarios provided by a state-of-the-art regional climate model (RCM). Anomalies of severalmeteorological variables were used as predictors and phenological anomalies of the flowering date of the test plantForsythiasuspensaas predictand. Several cross-validated prediction models using various numbers and differently constructed predictorswere developed, compared, and evaluated via bootstrapping. As our approach needs a small set of meteorological observationsper phenological station, it allows for reliable parameter estimation and an easy transfer to other regions. The most robust andsuccessful model comprises predictors based on mean temperature, precipitation, wind velocity, and snow depth. Its averagecoefficient of determination and root mean square error (RMSE) per station are 60\% and ± 8.6 days, respectively. However, theprediction error strongly differs among stations. When transferred to other indicator plants, this method achieves a comparablelevel of predictive accuracy. Its application to two climate change scenarios reveals distinct changes for various plants andregions. The flowering date is simulated to occur between 5 and 25 days earlier at the end of the twenty-first century comparedto the phenology of the reference period (1961-1990).}, language = {en} } @phdthesis{Krause2024, author = {Krause, Julian}, title = {Auswirkungen des Klimawandels auf charakteristische B{\"o}den in Unterfranken unter Ber{\"u}cksichtigung bodenhydrologischer Monitoringdaten (2018 bis 2022)}, doi = {10.25972/OPUS-36066}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-360668}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2024}, abstract = {Die mit dem Klimawandel einhergehenden Umweltver{\"a}nderungen, wie steigende Temperaturen, Abnahme der Sommer- und Zunahme der Winterniederschl{\"a}ge, h{\"a}ufigere und l{\"a}ngere Trockenperioden, zunehmende Starkniederschl{\"a}ge, St{\"u}rme und Hitzewellen betreffen besonders den Bodenwasserhaushalt in seiner zentralen Regelungsfunktion f{\"u}r den Landschaftswasserhaushalt. Von der Wasserverf{\"u}gbarkeit im Boden h{\"a}ngen zu einem sehr hohen Grad auch die Ertr{\"a}ge der Land- und Forstwirtschaft ab. Eine besonders große Bedeutung kommt dabei der Wasserspeicherkapazit{\"a}t der B{\"o}den zu, da w{\"a}hrend einer Trockenphase die effektiven Niederschl{\"a}ge den Wasserbedarf der Pflanzen nicht decken k{\"o}nnen und das bereits gespeicherte Bodenwasser das {\"U}berleben der Pflanzen sicherstellen kann. F{\"u}r die land- und forstwirtschaftlichen Akteure sind in diesem Kontext quantitative und qualitative Aussagen zu den Auswirkungen des Klimawandels auf den Boden essenziell, um die notwendigen Anpassungsmaßnahmen f{\"u}r ihre Betriebe treffen zu k{\"o}nnen. Zielsetzungen der vorliegenden Arbeit bestehen darin, die Dynamik der Bodenfeuchte in unterfr{\"a}nkischen B{\"o}den besser zu verstehen, die Datenlage zum Verlauf der Bodenfeuchte zu verbessern und die Auswirkungen von prognostizierten klimatischen Parametern absch{\"a}tzen zu k{\"o}nnen. Hierzu wurden an sechs f{\"u}r ihre jeweiligen Naturr{\"a}ume und hinsichtlich ihrer anthropogenen Nutzung charakteristischen Standorten meteorologisch-bodenhydrologische Messstationen installiert. Die Messstationen befinden sich in einem Rigosol auf Buntsandstein in einem Weinberg bei B{\"u}rgstadt sowie auf einer Parabraunerde im L{\"o}ssgebiet bei Herchsheim unter Ackernutzung. Am {\"U}bergang von Muschelkalk in Keuper befinden sich die Stationen in Obbach, wo eine Braunerde unter Ackernutzung vorliegt und im Forst des Universit{\"a}tswalds Sailershausen werden die Untersuchungen in einer Braunerde-Terra fusca durchgef{\"u}hrt. Im Forst befinden sich auch die Stationen in Oberrimbach mit Braunerden aus Sandsteinkeuper und in Willmars mit Braunerden aus Buntsandstein. Der Beobachtungszeitraum dieser Arbeit reicht von Juli 2018 bis November 2022. In diesen Zeitraum fiel die dreij{\"a}hrige D{\"u}rre von 2018 bis 2020, das Jahr 2021 mit einem durchschnittlichen Witterungsverlauf und das D{\"u}rrejahr 2022. Das Langzeitmonitoring wurde von umfangreichen Gel{\"a}nde- und Laboranalysen der grundlegenden bodenkundlichen Parameter der Bodenprofile und der Standorte begleitet. Die bodengeographischen-geomorphologischen Standortanalysen bilden zusammen mit den qualitativen Auswertungen der Bodenfeuchtezeitreihen die Grundlage f{\"u}r Einsch{\"a}tzungen zu den Auswirkungen des Klimawandels auf den Bodenwasserhaushalt. Verl{\"a}ssliche Aussagen zum Bodenwasserhaushalt k{\"o}nnen nur auf Grundlage von zeitlich und r{\"a}umlich hoch aufgel{\"o}sten Daten getroffen werden. Bodenfeuchtezeitreihen zusammen mit den bodenphysikalischen Daten lagen in dieser Datenqualit{\"a}t f{\"u}r Unterfranken bisher nur sehr vereinzelt vor. Die vorliegenden Ergebnisse zeigen, dass die untersuchten B{\"o}den entsprechend den jeweiligen naturr{\"a}umlichen Gegebenheiten sehr unterschiedliche bodenhydrologische Eigenschaften aufweisen. W{\"a}hrend langer Trockenphasen k{\"o}nnen beispielsweise die Parabraunerden am Standort Herchsheim wegen ihrer h{\"o}heren Wasserspeicherkapazit{\"a}t die Pflanzen l{\"a}nger mit Wasser versorgen als die sandigen Braunerden am Standort Oberrimbach. Die Bodenfeuchteregime im Beobachtungszeitraum waren sehr stark vom Witterungsverlauf einzelner Jahre abh{\"a}ngig. Das Bodenfeuchteregime bei einem durchschnittlichen Witterungsverlauf wie in 2021 zeichnet sich durch eine langsame Abnahme der Bodenfeuchte ab Beginn der Vegetationsperiode im Fr{\"u}hjahr aus. Regelm{\"a}ßige Niederschl{\"a}ge im Fr{\"u}hjahr f{\"u}llen den oberfl{\"a}chennahen Bodenwasserspeicher immer wieder auf und sichern den Bodenwasservorrat in der Tiefe bis in den Hochsommer. Im Hochsommer k{\"o}nnen Pflanzen dann w{\"a}hrend der Trockenphasen ihren Wasserbedarf aus den tieferen Horizonten decken. Im Gegensatz dazu nimmt die Bodenfeuchte in D{\"u}rrejahren wie 2018 bis 2020 oder 2022 bereits im Fr{\"u}hjahr bis in die untersten Horizonte stark ab. Die nutzbare Feldkapazit{\"a}t ist zum Teil schon im Juni weitgehend ausgesch{\"o}pft, womit f{\"u}r sp{\"a}tere Trockenphasen kein Bodenwasser mehr zur Verf{\"u}gung steht. Die Herbst- und Winterniederschl{\"a}ge s{\"a}ttigen den Bodenwasservorrat wieder bis zur Feldkapazit{\"a}t auf. Bei tiefreichender Ersch{\"o}pfung des Bodenwassers wurde die Feldkapazit{\"a}t erst im Januar oder Februar erreicht. Im Zuge der land- und forstwirtschaftlichen Nutzung ist eine gute Datenlage zu den bodenkundlichen und stand{\"o}rtlichen Gegebenheiten f{\"u}r klimaadaptierte Anpassungsstrategien essentiell. Wichtige Zielsetzungen bestehen grunds{\"a}tzlich in der Erhaltung der Bodenfunktionen, in der Verbesserung der Infiltrationskapazit{\"a}t und Wasserspeicherkapazit{\"a}t. Hier kommt dem Boden als interaktive Austauschfl{\"a}che zwischen den Sph{\"a}ren und damit dem Bodenschutz eine zentrale Bedeutung zu. Die in Zukunft erwarteten klimatischen Bedingungen stellen an jeden Boden andere Herausforderungen, welchen mit stand{\"o}rtlich abgestimmten Bodenschutzmaßnahmen begegnet werden kann.}, subject = {Bodengeografie}, language = {de} } @phdthesis{KanmegneTamga2024, author = {Kanmegne Tamga, Dan Emmanuel}, title = {Modelling Carbon Sequestration of Agroforestry Systems in West Africa using Remote Sensing}, doi = {10.25972/OPUS-36926}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-369269}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2024}, abstract = {The production of commodities such as cocoa, rubber, oil palm and cashew, is the main driver of deforestation in West Africa (WA). The practiced production systems correspond to a land managment approach referred to as agroforestry systems (AFS), which consist of managing trees and crops on the same unit of land.Because of the ubiquity of trees, AFS reported as viable solution for climate mitigation; the carbon sequestrated by the trees could be estimated with remote sensing (RS) data and methods and reported as emission reduction efforts. However, the diversity in AFS in relation to their composition, structure and spatial distribution makes it challenging for an accurate monitoring of carbon stocks using RS. Therefore, the aim of this research is to propose a RS-based approach for the estimation of carbon sequestration in AFS across the climatic regions of WA. The main objectives were to (i) provide an accurate classification map of AFS by modelling the spatial distribution of the classification error; (ii) estimate the carbon stock of AFS in the main climatic regions of WA using RS data; (iii) evaluate the dynamic of carbon stocks within AFS across WA. Three regions of interest (ROI) were defined in Cote d'Ivoire and Burkina Faso, one in each climatic region of WA namely the Guineo-Congolian, Guinean and Sudanian, and three field campaigns were carried out for data collection. The collected data consisted of reference points for image classification, biometric tree measurements (diameter, height, species) for biomass estimation. A total of 261 samples were collected in 12 AFS across WA. For the RS data, yearly composite images from Sentinel-1 and -2 (S1 and S2), ALOS-PALSAR and GEDI data were used. A supervised classification using random forest (RF) was implemented and the classification error was assessed using the Shannon entropy generated from the class probabilities. For carbon estimation, different RS data, machine learning algorithms and carbon reference sources were compared for the prediction of the aboveground biomass in AFS. The assessment of the carbon dynamic was carried between 2017 and 2021. An average carbon map was genrated and use as reference for the comparison of annual carbon estimations, using the standard deviation as threshold. As far as the results are concerned, the classification accuracy was higher than 0.9 in all the ROIs, and AFS were mainly represented by rubber (38.9\%), cocoa (36.4\%), palm (10.8\%) in the ROI-1, mango (15.2\%) and cashew (13.4\%) in ROI-2, shea tree (55.7\%) and African locust bean (28.1\%) in ROI-3. However, evidence of misclassification was found in cocoa, mango, and shea butter. The assessment of the classification error suggested that the error level was higher in the ROI-3 and ROI-1. The error generated from the entropy was able to reduced the level of misclassification by 63\% with 11\% of loss of information. Moreover, the approach was able to accuretely detect encroachement in protected areas. On carbon estimation, the highest prediction accuracy (R²>0.8) was obtained for a RF model using the combination of S1 and S2 and AGB derived from field measurements. Predictions from GEDI could only be used as reference in the ROI-1 but resulted in a prediction error was higher in cashew, mango, rubber and cocoa plantations, and the carbon stock level was higher in African locust bean (43.9 t/ha), shea butter (15 t/ha), cashew (13.8 t/ha), mango (12.8 t/ha), cocoa (7.51 t/ha) and rubber (7.33 t/ha). The analysis showed that carbon stock is determined mainly by the diameter (R²=0.45) and height (R²=0.13) of trees. It was found that crop plantations had the lowest biodiversity level, and no significant relationship was found between the considered biodiversity indices and carbon stock levels. The assessment of the spatial distribution of carbon sources and sinks showed that cashew plantations are carbon emitters due to firewood collection, while cocoa plantations showed the highest potential for carbon sequestration. The study revealed that Sentinel data could be used to support a RS-based approach for modelling carbon sequestration in AFS. Entropy could be used to map crop plantations and to monitor encroachment in protected areas. Moreover, field measurements with appropriate allometric models could ensure an accurate estimation of carbon stocks in AFS. Even though AFS in the Sudanian region had the highest carbon stocks level, there is a high potential to increase the carbon level in cocoa plantations by integrating and/or maintaining forest trees.}, subject = {Sequestrierung}, language = {en} }