550 Geowissenschaften
Refine
Has Fulltext
- yes (108)
Is part of the Bibliography
- yes (108)
Year of publication
Document Type
- Journal article (108) (remove)
Keywords
- remote sensing (15)
- Geographie (8)
- climate change (6)
- time series (6)
- Niger (5)
- earth observation (5)
- forest (5)
- review (5)
- MODIS (4)
- Sentinel-1 (4)
- drought (4)
- machine learning (4)
- Earth Observation (3)
- Earth observation (3)
- Landsat (3)
- South Africa (3)
- dynamics (3)
- land cover (3)
- permafrost (3)
- Antarctic ice sheet (2)
- Antarctica (2)
- Geologie (2)
- Germany (2)
- Google Earth Engine (2)
- Kilombero (2)
- NDVI (2)
- SAR (2)
- Sahara (2)
- Sentinel-2 (2)
- TanDEM-X (2)
- biodiversity (2)
- change detection (2)
- deep learning (2)
- forecast (2)
- forest ecology (2)
- geomorphology (2)
- glaciers (2)
- global change (2)
- hydrology (2)
- land use (2)
- movement ecology (2)
- object-based classification (2)
- optical remote sensing (2)
- probability (2)
- random forest (2)
- satellite data (2)
- supraglacial lakes (2)
- time series analysis (2)
- wetland (2)
- 3D (1)
- 3D remote sensing (1)
- 3‐D electrical resistivity imaging (1)
- AVHRR (1)
- Aggeneys (1)
- Alps (1)
- Analyse (1)
- Angola (1)
- Animal Tracking (1)
- Antarktis (1)
- Asia (1)
- Bavaria (1)
- Bilma <Region> (1)
- Biostratigraphy (1)
- Blue Spot Analysis (1)
- Broken Hill (1)
- CORDEX Africa (1)
- Cambrian (1)
- Covid‐19 (1)
- DEM (1)
- DEUQUA (1)
- DInSAR (1)
- DSM (1)
- Dongting Lake (1)
- ERT (1)
- Einzelhandel (1)
- El Niño (1)
- Elissen-Palm flux (1)
- Erbendorf (1)
- Erholungsplanung (1)
- Europe (1)
- Extreme flows (1)
- Eyjafjallajökull 2010 (1)
- Fractional cover analysis (1)
- Fulgurite (1)
- GEDI (1)
- GPS-Tracking (1)
- GSV (1)
- Gamsberg (1)
- Ghana (1)
- GlobALS (1)
- Global Ecosystem Dynamics Investigation (1)
- Google Earth Engine (GEE) (1)
- Greenland ice sheet (1)
- Herodotus (1)
- Himalaya Karakoram (1)
- Holocene (1)
- Holozän (1)
- Hunsrueck (1)
- InSAR (1)
- InSAR height (1)
- Indus-Ganges-Brahmaputra-Meghna (1)
- Isheru (1)
- Karst (1)
- Karstverfüllungen (1)
- Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland (1)
- Kunduz River Basin (1)
- LST (1)
- Land Change Modeler (1)
- Landsat archive (1)
- Landsat time series (1)
- Lantana camara (1)
- LiDAR (1)
- MODIS time-series (1)
- Mann-Kendall test (1)
- Markov chains (1)
- Mekong (1)
- Mikrosonde (1)
- Mineralogie (1)
- Morocco (1)
- NDVI thresholds (1)
- Nachhaltigkeitstransformation (1)
- Namibia (1)
- Neolithic (1)
- Niger <Ost> (1)
- Nile delta (1)
- Nile flow (1)
- Nordvictorialand (1)
- Oman (1)
- Oshana (1)
- Ostniger (1)
- PEST (1)
- Pakistan (1)
- Paläoklima (1)
- PlanetScope (1)
- Pleistozän (1)
- R (1)
- Ramsar Convention on Wetlands (1)
- RapidEye (1)
- Reliefgeschichte (1)
- SBAS (1)
- SDG 11.3.1 (1)
- SOC content prediction (1)
- SPOT-6 (1)
- SWAT (1)
- SWAT model (1)
- Sahel (1)
- Sandstein (1)
- Scenario analysis (1)
- Schmuckperle (1)
- Sebennitic (1)
- Sentine-1 (1)
- Sentinel–1 (1)
- Silicate (1)
- Snow Line Elevation (1)
- Soil and Water Assessment Tool (SWAT) (1)
- Southeast Asia (1)
- Swabian Alb (1)
- Systematics (1)
- Sápmi (1)
- TIMELINE (1)
- Tanzania (1)
- Tell Basta (1)
- Tepl-Taus (1)
- Tian Shan (1)
- Trilobita (1)
- UAV (1)
- Uzbekistan (1)
- Vohenstrauß (1)
- WaSiM-ETH (1)
- West Africa (1)
- West Gondwana (1)
- Western Cape (1)
- Western Europe (1)
- Wilson Terrane (1)
- Wilson Terrane ; intrusions ; mafic composition ; relative age ; petrographic analysis ; gabbroic composition ; subduction zones (1)
- Zambia (1)
- accuracy (1)
- agricultural drought (1)
- agricultural mapping (1)
- agriculture (1)
- air quality (1)
- alpha diversity (1)
- ancient Egypt (1)
- anthroposphere (1)
- aquaculture (1)
- atmospheric circulation (1)
- atmospheric correction (1)
- atmospheric waves (1)
- automatic processing (1)
- base metal deposit (1)
- beech (1)
- beta diversity (1)
- big earth data (1)
- biosphere (1)
- black carbon AOD (1)
- boreholes (1)
- burned area (1)
- calc-silicate rocks; fluid behaviour; P-T path; reaction textures; Variscan basement; very high-pressure metamorphism (1)
- canopy height (1)
- causal networks (1)
- change vector analysis (1)
- circulation patterns (1)
- circulation type (1)
- circum-Arctic (1)
- class homogeneity (1)
- climate extremes (1)
- climate related trends (1)
- climate scenarios (1)
- climatic change (1)
- coal (1)
- coal fire (1)
- coal mining area (1)
- coastal erosion (1)
- coastal zone (1)
- coastline dynamics (1)
- composition (1)
- conservation (1)
- consumptive water use (1)
- convolutional neural network (1)
- crop statistics (1)
- cryosphere (1)
- culturable command area (1)
- damage assessment disaster (1)
- database (1)
- debris-covered glaciers (1)
- digitalisation initiative (1)
- disaster (1)
- distributary (1)
- diurnal (1)
- drainage ratio (1)
- drilling (1)
- driving forces (1)
- drought impact (1)
- drought stress indicators (1)
- eCognition (1)
- earthquake (1)
- electrical resistivity tomography (1)
- emissivity (1)
- energy (1)
- entrainment (1)
- environmental justice (1)
- environmental modeling (1)
- error estimation (1)
- eruption rate (1)
- evapotranspiration (1)
- explosive volcanism (1)
- e‐commerce (1)
- feature tracking (1)
- fire (1)
- flood (1)
- floodpath lake (1)
- food production (1)
- forest disturbances (1)
- forest hydrology (1)
- forest monitoring (1)
- forest resources inventory (1)
- forest structure Germany (1)
- framing (1)
- fulgurites (1)
- function (1)
- galamsey (1)
- gamma diversity (1)
- general circulation model (1)
- geoarchaeology (1)
- geomorphologie (1)
- gis (1)
- global (1)
- global warming (1)
- grassland (1)
- ground penetrating radar (1)
- groundwater (1)
- ground‐penetrating radar (1)
- harmonization (1)
- hazard maps (1)
- heat wave (1)
- historical (1)
- hotspot analysis (1)
- human disturbance (1)
- human pressure (1)
- hydrological drought (1)
- hydrological modelling (1)
- hydrological regime (1)
- ice sheet dynamics (1)
- ice sheet hydrology (1)
- image (1)
- image artifacts (1)
- impervious surface (1)
- indicator importance assessment (1)
- infrasound (1)
- integration (1)
- intercomparison (1)
- interferometry (1)
- interpolation (1)
- inundation (1)
- inverse parameterization (1)
- irrigated agriculture (1)
- irrigation (1)
- irrigation pricing (1)
- jet stream (1)
- jets (1)
- karst siliceux (1)
- land cover change (1)
- land surface (1)
- land surface temperature (1)
- land surface temperature (LST) (1)
- land use change (1)
- land use/cover pattern (LUCP) (1)
- land-use/land-cover change (1)
- landcover changes (1)
- landsat (1)
- landscape metrics (1)
- landslides (1)
- large‐scale atmospheric circulation modes (1)
- lava (1)
- letzte Meile (1)
- lightning (1)
- loess plateau (1)
- lokaler Onlinemarktplatz (1)
- loss (1)
- low-cost applications (1)
- management (1)
- mass (1)
- metamorphic sulfidation (1)
- meteorological drought (1)
- mineralization (1)
- mining (1)
- modeling (1)
- models (1)
- mountains (1)
- multi-sensor (1)
- multi-spectral (1)
- multispectral VNIR (1)
- multitemporal metrics (1)
- multi‐model ensemble (1)
- nature conservation (1)
- near-field monitoring (1)
- near-surface geophysics (1)
- networking (1)
- nu SVR (1)
- object-based image analysis (1)
- oil spill (1)
- optical diversity (1)
- optimization (1)
- palaeoclimatology (1)
- palaeontology (1)
- palaeosols (1)
- paleoclimate (1)
- paleoenvironment (1)
- palsa development (1)
- paléoclimat (1)
- pan (1)
- partial correlation (1)
- peatland (1)
- penetration bias (1)
- performance assessment (1)
- periglacial (1)
- periurban (1)
- phenology (1)
- pilot-point-approach (1)
- platform economy (1)
- plumes (1)
- polarimetery (1)
- pollution (1)
- ponds (1)
- population change (1)
- post-classification comparison (1)
- predictive performance (1)
- preface (1)
- protection status (1)
- pulsating explosive eruptions (1)
- radar (1)
- random forest regression (1)
- regional climate model (1)
- reliability (1)
- renewable energy (1)
- resource mapping (1)
- resource suitability (1)
- retrogressive thaw slump (1)
- river discharge (1)
- robust change vector analysis (1)
- rock glaciers (1)
- sacred lakes (1)
- sar (1)
- satellite remote sensing (1)
- scenario analysis (1)
- seasonal (1)
- seasonal dynamics (1)
- seasonality (1)
- sedimentology (1)
- segmentation (1)
- semantic segmentation (1)
- sensitivity analysis (1)
- sentinel (1)
- sentinel-2 (1)
- silicate karst (1)
- slope bogs (1)
- snow cover area (1)
- snow hydrology (1)
- snow parameters (1)
- snow variability (1)
- snowmelt runoff model (1)
- soil matric potential (1)
- source parameters (1)
- southern annular mode (1)
- spatial analysis (1)
- spatial scale (1)
- spatial water balance (1)
- spatiotemporal slump development (1)
- species (1)
- spectral diversity (1)
- spectral variation hypothesis (1)
- spring flood (1)
- statistical modeling (1)
- storage volume (1)
- stream flow (1)
- structure (1)
- sub-pixel coastline extraction (1)
- subpixel (1)
- subsidence (1)
- subsurface hydrology (1)
- sulfide inclusions (1)
- surface melt (1)
- surface reflectances (1)
- surface urban heat island (SUHI) (1)
- surface water (1)
- surface water area (1)
- sustainable irrigation system (1)
- synthetic aperture RADAR (1)
- tasselled cap (1)
- temperature (1)
- thermal infrared (1)
- thunderstorms (1)
- tikhonov regularization (1)
- time-series features (1)
- training sample migration (1)
- trend analysis (1)
- trends (1)
- two‐sided markets (1)
- uncertainties (1)
- uncertainty (1)
- uneven-aged mountainous (1)
- urban climate (1)
- urban environments (1)
- urbane Logistik (1)
- vDEUQUA2021 (1)
- validation (1)
- value of water (1)
- variability (1)
- vegetation indices (1)
- vegetation restoration (1)
- volcano (1)
- volcanoes (1)
- water (1)
- water balance (1)
- water dynamics (1)
- water management (1)
- water retention (1)
- water yield (1)
- wetland mapping (1)
- wind speed (1)
Institute
EU-Project number / Contract (GA) number
- 20-3044-2-11 (1)
- 308377 (1)
- 776019 (1)
Mapping aquaculture ponds for the coastal zone of Asia with Sentinel-1 and Sentinel-2 time series
(2021)
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.
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.
No abstract available.
No abstract available
No abstract available
Wind energy is a key option in global dialogues about climate change mitigation. Here, we combined observations from surface wind stations, reanalysis datasets, and state‐of‐the‐art regional climate models from the Coordinated Regional Climate Downscaling Experiment (CORDEX Africa) to study the current and future wind energy potential in Zambia. We found that winds are dominated by southeasterlies and are rarely strong with an average speed of 2.8 m·s\(^{−1}\). When we converted the observed surface wind speed to a turbine hub height of 100 m, we found a ~38% increase in mean wind speed for the period 1981–2000. Further, both simulated and observed wind speed data show statistically significant increments across much of the country. The only areas that divert from this upward trend of wind speeds are the low land terrains of the Eastern Province bordering Malawi. Examining projections of wind power density (WPD), we found that although wind speed is increasing, it is still generally too weak to support large‐scale wind power generation. We found a meagre projected annual average WPD of 46.6 W·m\(^{−2}\). The highest WPDs of ~80 W·m\(^{−2}\) are projected in the northern and central parts of the country while the lowest are to be expected along the Luangwa valley in agreement with wind speed simulations. On average, Zambia is expected to experience minor WPD increments of 0.004 W·m\(^{−2}\) per year from 2031 to 2050. We conclude that small‐scale wind turbines that accommodate cut‐in wind speeds of 3.8 m·s\(^{−1}\) are the most suitable for power generation in Zambia. Further, given the limitations of small wind turbines, they are best suited for rural and suburban areas of the country where obstructions are few, thus making them ideal for complementing the government of the Republic of Zambia's rural electrification efforts.
By 2050, two-third of the world’s population will live in cities. In this study, we develop a framework for analyzing urban growth-related imperviousness in North Rhine-Westphalia (NRW) from the 1980s to date using Landsat data. For the baseline 2017-time step, official geodata was extracted to generate labelled data for ten classes, including three classes representing low, middle, and high level of imperviousness. We used the output of the 2017 classification and information based on radiometric bi-temporal change detection for retrospective classification. Besides spectral bands, we calculated several indices and various temporal composites, which were used as an input for Random Forest classification. The results provide information on three imperviousness classes with accuracies exceeding 75%. According to our results, the imperviousness areas grew continuously from 1985 to 2017, with a high imperviousness area growth of more than 167,000 ha, comprising around 30% increase. The information on the expansion of urban areas was integrated with population dynamics data to estimate the progress towards SDG 11. With the intensity analysis and the integration of population data, the spatial heterogeneity of urban expansion and population growth was analysed, showing that the urban expansion rates considerably excelled population growth rates in some regions in NRW. The study highlights the applicability of earth observation data for accurately quantifying spatio-temporal urban dynamics for sustainable urbanization and targeted planning.
Digital platforms, such as Amazon, represent the major beneficiaries of the Covid‐19 crisis. This study examines the role of digital platforms and their engagement in digitalisation initiatives targeting (small) brick‐and‐mortar retailers in Germany, thereby contributing to a better understanding of how digital platforms augment, substitute or reorganise physical retail spaces. This study applies a mixed‐method approach based on qualitative interviews, participant observation as well as media analysis. First, the study illustrates the controversial role of digital platforms by positioning themselves as supporting partners of the (offline) retailers, while simultaneously shifting power towards the platforms themselves. Second, digital platforms have established themselves not only as infrastructure providers but also as actors within these infrastructures, framing digital as well as physical retail spaces, inter alia due to their role as publicly legitimised retail advisers. Third, while institutions want to help retailers to survive, they simultaneously enhance retailers' dependency on digital platforms.
Die Arbeit beschreibt im ersten Teil die Auswirkung der Sandstein- und Eisenkrustenverkarstung auf das Plateaurelief des östlichen Niger. Angesprochen werden die abflußlosen Karstdepressionen auf den Plateaudachflächen, die Rolle intensiver Verkarstung bei der Herauspräparierung von Sandsteinsäulen an Hängen, von Plateauspornen und Inselbergen, die Mitwirkung bei der Talbildung sowie Einsturzdolinen an Hängen. Im zweiten Teil wird die Mikromorphologie von Karsthöhlenüberzügen aus der Endphase der phreatischen Karstlösung beschrieben. Oberflächennahe Körner weisen starke Korrosion auf. Phosphor in der wiederausgefällten Matrix und eingekieselte Bakterien deuten auf eine organische Komponente bei der Ausbildung des tertiären Silikatkarsts.
Advances in remote inventory and analysis of forest resources during the last decade have reached a level to be now considered as a crucial complement, if not a surrogate, to the long-existing field-based methods. This is mostly reflected in not only the use of multiple-band new active and passive remote sensing data for forest inventory, but also in the methodic and algorithmic developments and/or adoptions that aim at maximizing the predictive or calibration performances, thereby minimizing both random and systematic errors, in particular for multi-scale spatial domains. With this in mind, this editorial note wraps up the recently-published Remote Sensing special issue “Remote Sensing-Based Forest Inventories from Landscape to Global Scale”, which hosted a set of state-of-the-art experiments on remotely sensed inventory of forest resources conducted by a number of prominent researchers worldwide.
Sufficient plant-available water is one of the most important requirements for vital, stable, and well-growing forest stands. In the face of climate change, there are various approaches to derive recommendations considering tree species selection based on plant-available water provided by measurements or simulations. Owing to the small-parcel management of Central European forests as well as small-spatial variation of soil and stand properties, in situ data collection for individual forest stands of large areas is not feasible, considering time and cost effort. This problem can be addressed using physically based modeling, aiming to numerically simulate the water balance. In this study, we parameterized, calibrated, and verified the hydrological multidimensional WaSiM-ETH model to assess the water balance at a spatial resolution of 30 m in a German forested catchment area (136.4 km2) for the period 2000–2021 using selected in situ data, remote sensing products, and total runoff. Based on the model output, drought-sensitive parameters, such as the difference between potential and effective stand transpiration (Tdiff) and the water balance, were deduced from the model, analyzed, and evaluated. Results show that the modeled evapotranspiration (ET) correlated significantly (R2 = 0.80) with the estimated ET using MODIS data (MOD16A2GFv006). Compared with observed daily, monthly, and annual runoff data, the model shows a good performance (R2: 0.70|0.77|0.73; Kling–Gupta efficiency: 0.59|0.62|0.83; volumetric efficiency: 0.52|0.60|0.83). The comparison with in situ data from a forest monitoring plot, established at the end of 2020, indicated good agreement between observed and simulated interception and soil water content. According to our results, WaSiM-ETH is a potential supplement for forest management, owing to its multidimensionality and the ability to model soil water balance for large areas at comparable high spatial resolution. The outputs offer, compared to non-distributed models (like LWF-Brook90), spatial differentiability, which is important for small-scale parceled forests, regarding stand structure and soil properties. Due to the spatial component offered, additional verification possibilities are feasible allowing a reliable and profound verification of the model and its parameterization.
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.
Atmospheric circulation is a key driver of climate variability, and the representation of atmospheric circulation modes in regional climate models (RCMs) can enhance the credibility of regional climate projections. This study examines the representation of large‐scale atmospheric circulation modes in Coupled Model Inter‐comparison Project phase 5 RCMs once driven by ERA‐Interim, and by two general circulation models (GCMs). The study region is Western Europe and the circulation modes are classified using the Promax rotated T‐mode principal component analysis. The results indicate that the RCMs can replicate the classified atmospheric modes as obtained from ERA5 reanalysis, though with biases dependent on the data providing the lateral boundary condition and the choice of RCM. When the boundary condition is provided by ERA‐Interim that is more consistent with observations, the simulated map types and the associating time series match well with their counterparts from ERA5. Further, on average, the multi‐model ensemble mean of the analysed RCMs, driven by ERA‐Interim, indicated a slight improvement in the representation of the modes obtained from ERA5. Conversely, when the RCMs are driven by the GCMs that are models without assimilation of observational data, the representation of the atmospheric modes, as obtained from ERA5, is relatively less accurate compared to when the RCMs are driven by ERA‐Interim. This suggests that the biases stem from the GCMs. On average, the representation of the modes was not improved in the multi‐model ensemble mean of the five analysed RCMs driven by either of the GCMs. However, when the best‐performed RCMs were selected on average the ensemble mean indicated a slight improvement. Moreover, the presence of the North Atlantic Oscillation (NAO) in the simulated modes depends also on the lateral boundary conditions. The relationship between the modes and the NAO was replicated only when the RCMs were driven by reanalysis. The results indicate that the forcing model is the main factor in reproducing the atmospheric circulation.
The monitoring of land cover and land use change is critical for assessing the provision of ecosystem services. One of the sources for long-term land cover change quantification is through the classification of historical and/or current maps. Little research has been done on historical maps using Object-Based Image Analysis (OBIA). This study applied an object-based classification using eCognition tool for analyzing the land cover based on historical maps in the Main river catchment, Upper Franconia, Germany. This allowed land use change analysis between the 1850s and 2015, a time span which covers the phase of industrialization of landscapes in central Europe. The results show a strong increase in urban area by 2600%, a severe loss of cropland (−24%), a moderate reduction in meadows (−4%), and a small gain in forests (+4%). The method proved useful for the application on historical maps due to the ability of the software to create semantic objects. The confusion matrix shows an overall accuracy of 82% for the automatic classification compared to manual reclassification considering all 17 sample tiles. The minimum overall accuracy was 65% for historical maps of poor quality and the maximum was 91% for very high-quality ones. Although accuracy is between high and moderate, coarse land cover patterns in the past and trends in land cover change can be analyzed. We conclude that such long-term analysis of land cover is a prerequisite for quantifying long-term changes in ecosystem services.
The overarching goal of this research was to explore accurate methods of mapping irrigated crops, where digital cadastre information is unavailable: (a) Boundary separation by object-oriented image segmentation using very high spatial resolution (2.5–5 m) data was followed by (b) identification of crops and crop rotations by means of phenology, tasselled cap, and rule-based classification using high resolution (15–30 m) bi-temporal data. The extensive irrigated cotton production system of the Khorezm province in Uzbekistan, Central Asia, was selected as a study region. Image segmentation was carried out on pan-sharpened SPOT data. Varying combinations of segmentation parameters (shape, compactness, and color) were tested for optimized boundary separation. The resulting geometry was validated against polygons digitized from the data and cadastre maps, analysing similarity (size, shape) and congruence. The parameters shape and compactness were decisive for segmentation accuracy. Differences between crop phenologies were analyzed at field level using bi-temporal ASTER data. A rule set based on the tasselled cap indices greenness and brightness allowed for classifying crop rotations of cotton, winter-wheat and rice, resulting in an overall accuracy of 80 %. The proposed field-based crop classification method can be an important tool for use in water demand estimations, crop yield simulations, or economic models in agricultural systems similar to Khorezm.
The Ringgold Knoll pegmatite, a late-stage member of the Granite Harbour Intrusives, crosscuts high-grade Wilson gneisses of the Oates Coast, which forms the westernmost part of the Wilson Terrane at the Pacific end of the Cambro-Ordovician Ross orogenic belt in West Antarctica. The pegmatite mineral assemblage consists of K-feldspar, plagioclase, quartz, garnet (almandinespessartine-pyrope), dark tourmaline (schorl-dravite), muscovite, apatite, monazite, zircon, blue AI-rich tourmaline and dumortierite in order of decreasing abundances. Major, minor and rare earth elements are reported for the greater part of the mineral assemblage. The time of pegmatite emplacement is constrained by Rb-Sr and Sm-Nd isochron ages of 492 ± 8 (2a) Ma and 500 ± 40 (2a) Ma, respectively. High initial 87Sr/86Sr of 0.7315 ± 0.0003 and low E Nd,t of -8.7 ± 1.2 strongly support an origin of the magma from highly evolved crustal source rocks. K-Ar and Ar-Ar model ages of about 470 to 475 Ma for igneous muscovite indicate that the pegmatite together with its wall rocks spent a prolonged period at elevated temperatures before final cooling below about 350 °C. The muscovite dates may give an estimate for the time of exhumation of the Oates Coast crystalline basement along two major late Ross orogenic detachment zones within the Wilson Terrane i.e. the Wilson and the Exiles thrusts (c.f. FLÖTTMANN and KLEINSCHMIDT, 1991).
An Metabasiten der Zone Erbendorf-Vohenstrauß, der Erbendorfer Grünschieferzone und der Zone Tirschenreuth-Mähring wurden petrographische, geochemische und phasenpetrologische Untersuchungen sowie K-Ar-Mineraldatierungen durchgeführt. In der Zone Erbendorf-Vohenstrauß treten in regionaler Abhängigkeit drei Haupttypen von Metabasiten auf: 1. Flaseramphibolite mit der Paragenese Hornblende + Oligoklas/ Andesin + Granat ± Salit und mit Plagioklas- und / oder Kalksilikat-reichen Flasern findet man hauptsächlich im nördlichen und zentralen Teil der Zone Erbendorf-Vohenstrauß. Geochemisch zeigen sie eine deutliche Anreicherung der inkompatiblen Elemente und der leichten Seltenerdelemente und sind vergleichbar mit modernen Tholeiiten von ozeanischen Inseln oder anomalen Abschnitten mittelozeanischer Rükken. Ein kontinentaler Intraplatten-Charakter scheint nicht gegeben. In der Kontaktaureole von Windisch-Eschenbach wurde ein Teil der Flaseramphibolite kontaktmetamorph überprägt. 2. Schiefrige, teils streifige Amphibolite mit der Paragenese Hornblende + Andesin / Labrador ± Salit dominieren im Süd teil der Zone Erbendorf-Vohenstrauß, erscheinen aber in einzelnen Ausstrichen auch im Norden. Die Streifung entsteht durch Plagioklas- und / oder Kalksilikat-reiche Zwischenlagen. Geochemisch sind diese Amphibolite bei flachen Spurenelement- und Seltenerdelement- Mustern vergleichbar mit modernen Tholeiiten von normalen Abschnitten mittelozeanischer Rücken. Sowohl Flaseramphibolite als auch schiefrige, teils streifige Amphibolite zeigen Übergänge zu massigen, homogenen Amphiboliten. 3. Metagabbros mit der Paragenese Hornblende + Plagioklas ± Biotit und einer grobkörnigen, gabbro iden Textur treten hauptsächlich im Bereich der Schuppenzone Michldorf-Kaimling (VOLL 1960) auf. Geochemisch nehmen sie bei einer schwachen Anreicherung der inkompatiblen Elemente eine Zwischenstellung zwischen Flaseramphiboliten und schiefrigen, teils streifigen Amphiboliten ein. In der Erbendorfer Grünschieferzone treten Metagabbros und schiefrige, teils gestreifte Amphibolite mit der Paragenese Hornblende + Oligoklas ± Epidot ± Chlorit auf. Die Amphibolite wurden z. T. stark retrograd überprägt und dabei auch deformiert. Dies wird auf größere, post-regionalmetamorphe, tektonische Bewegungen, möglicherweise Deckenüberschiebungen zurückgeführt. Geochemisch sind die Metabasite der Erbendorfer Grünschieferzone mit modernen tholeiitischen bis kalkalkalischen, subduktionsgebundenen Basalten vergleichbar. Sie unterscheiden sich damit völlig von den südlich angrenzenden Flaseramphiboliten der Zone Erbendorf-Vohenstrauß und den nördlich benachbarten Amphiboliten des Fichtelgebirges. Dies unterstreicht die Stellung der Erbendorfer Grünschieferzone als eigenständige tektonische Einheit. Im Vergleich mit dem Münchberger Komplex zeigt die Erbendorfer Grünschieferzone große Ähnlichkeit mit der Prasinit-Phyllit-Serie hinsichtlich der tektonischen Stellung, der Lithologie und insbesondere des geochemischen Charakters der Metabasite. Zwischen der Zone Erbendorf-Vohen-strauß und den Münchberger Serien konnten bezüglich der Metabasite dagegen keine Parallelen festgestellt werden. Schiefrige, teils streifige Amphibolite der Zone Tirschenreuth-Mähring mit der Paragenese Hornblende + Andesin ± Salit (± Granat) und hellen Plagioklas- oder Kalksilikat-reichen Lagen sind geochemisch mit modernen Basalten normaler mittel ozeanischer Rücken vergleichbar. Die untersuchten Metabasite dürften die Zusammensetzung des basaltischen Ausgangsmaterials zumindest annähernd wiedergeben. In einigen Fällen wurde jedoch eine sekundäre Mobilisation von Elementen festgestellt: Die kontaktmetamorphe Überprägung eines Teils der Flaseramphibolite in der Kontaktaureole von Windisch-Eschenbach führte zu einer deutlichen Anreicherung von Rb, Li und K und zu einer Abreicherung von Ca, Sr und V, insbesondere aber von Cr und Ni. Die sog. immobilen Elemente Nb, Ce, (P), Zr, Ti, Y, Sc streuen in einem deutlich breiteren Bereich als bei den nicht kontaktmetamorphen Flaseramphiboliten. In einer Probe sind die Seltenerdelemente insgesamt angereichert. Eine Mobilisation von P20 S und den leichten Seltenerdelementen in einigen schiefrigen, teils streifigen Amphiboliten der Zone Erbendorf-Vohenstrauß und in einigen kontaktmetamorphen Flaseramphiboliten wird auf einen Abbau von Apatit im Zuge einer post-regionalmetamorphen, möglicherweise postgranitischen, hydrothermalen Überprägung zurückgeführt. Mineralchemische Untersuchungen ergaben für die Zusammensetzung der Hornblenden aus Amphiboliten der Zone Erbendorf-Vohenstrauß deutliche regionale Unterschiede, die weitgehend unabhängig von der regionalen Verteilung der einzelnen Metabasit-Haupttypen sind. Vergleichende Untersuchungen an Granat untermauern eine vermutete, frühere, eklogitfazielle Überprägung eines Granatamphibolits vom Nordrand der Zone Erbendorf-Vohenstrauß bei Hauxdorf. K-Ar-Altersdatierungen an Hornblende- und Glimmerkonzentraten belegen, daß das letzte, (Mitteldruck-) metamorphe Ereignis im Westteil der Zone Erbendorf-Vohenstrauß vor etwa 380 Ma beendet war. Dieses Alter wird korreliert mit einer letzten Metamorphose der höhermetamorphen Serien des Münchberger Komplexes zur gleichen Zeit. Im Ostteil der Zone Erbendorf-Vohenstrauß treten jüngere Altersdaten mit einem Schwerpunkt bei 324 Ma auf, die entweder auf einen Einfluß der etwa gleichalten Niederdruck-Metamorphose im unmittelbar benachbarten Moldanubikum i. e. S. oder auf die Intrusion des 324 Ma alten (KÖHLER et al. 1974) Leuchtenberger Granits zurückzuführen sind. Im Übergangsbereich vom Saxothuringikum zum Moldanubikum bei Mähring zeigen Altersdaten um 320Ma das Ende der letzten (Niederdruck-)Metamorphose an.
Dans le Niger oriental, des phénomenes karstiques sont fréquents dans les roches siliceuses: gres, silcretes, croûtes ferrugineuses, roches cristallines. A partir des études géomorphologiques et micromorphologiques, on peut conclure a une kartsification, au sense de production de formes par dissolution. Les résultats permettent de dater du Tertiaire inférieur la principale période de karstification. La répartition régionale des formes induites par cette karstification indique une dépendance probable des conditions paléoclimatiques. Actuellement le karst influe encore sur le développement des autres formes de relief.