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March 2011 - present
Publications
Publications (87)
Africa has the most dynamic demographic development worldwide. Current projections predict a population of > 3 billion people by the end of the century. Sub-Saharan Africa alone will likely see a 40% increase in population between 2020 and 2050. Although it is well known that large parts of Africa are in a constant state of water stress, its surfac...
Water availability is vital for the sustenance of livelihoods in the Lake Chad Basin. However, the daily and seasonal dynamics of open water bodies are not well understood. This study aims to (1) analyze the daily and seasonal dynamics of water bodies, (2) estimate changes in surface water area extent including trends and change points, and (3) ass...
With temperatures in Central Asia (CA) increasing more than the global average, this region is one of the global hotspots affected by climate change. CA is mostly characterized by arid climate, which is why available water resources are of paramount importance for the societies, economies, and the environment. In this regard, quantifying changes on...
The Lake Chad is an endorheic lake in Sahelian Africa, with an extension to hyper arid areas. The
lake basin is not exempt from global environmental changes which significantly affect fresh water
resources across the globe. Despite a plethora of research on lake Chad, the daily and seasonal
surface water dynamics is not clearly understood. This stu...
Open surface water across the globe is essential for many life forms and is an important source for human settlements, agriculture, and industry. The presence and variation in time and space is influenced by different natural conditions (e.g. climate, topography, geology) and human use (e.g. irrigation, flood protection). The information on the spa...
Negative impacts on agricultural activities by different locust species are well documented and have always been one of the major threats to food security and livelihoods, especially for local communities. Locust management and control have led to less frequent and intense plagues and outbreaks worldwide. However, political insecurity and armed con...
The Moroccan locust has been considered one of the most dangerous agricultural pests in the Mediterranean region. The economic importance of its outbreaks diminished during the second half of the 20th century due to a high degree of agricultural industrialization and other human-caused transformations of its habitat. Nevertheless, in Sardinia (Ital...
The Indo-Gangetic river basins feature a wide range of climatic, topographic, and land cover characteristics providing a suitable setting for the exploration of multivariate time series. Here, we collocated a comprehensive feature space for these river basins including Earth observation time series on the normalized difference vegetation index (NDV...
The goal of this research was to explore whether ecological niche modelling (ENM) and a habitat suitability index (HSI) model can be combined to refine results for actual breeding areas of three different locust pests. With the application of ENM as part of HSI, the information value based on climatic and soil preference components defining locust...
Inland surface water is often the most accessible freshwater source. As opposed to groundwater, surface water is replenished in a comparatively quick cycle, which makes this vital resource—if not overexploited—sustainable. From a global perspective, freshwater is plentiful. Still, depending on the region, surface water availability is severely limi...
High mountain Asia holds the largest glacier mass on Earth outside the polar regions. In combination with monsoonal rainfall, glacial meltwater provides the downstream Indo-Gangetic river basins with indispensable water resources. These rivers supply 1.2 billion people with water and their water resources are essential for many sectors including th...
In this study, we present a fused multi-scale approach to model habitat suitability index (HSI) maps for three different locust species. The presented methodology was applied for the Italian locust (Calliptamus italicus, CIT) in Pavlodar oblast, Northern Kazakhstan, for the Moroccan locust (Dociostaurus maroccanus, DMA) in Turkistan oblast, South K...
Earth Observation satellite data allows for the monitoring of the surface of our planet at predefined intervals covering large areas. However, there is only one medium resolution sensor family in orbit that enables an observation time span of 40 and more years at a daily repeat interval. This is the AVHRR sensor family. If we want to investigate th...
Earth observation time series are well suited to monitor global surface dynamics. However, data products that are aimed at assessing large-area dynamics with a high temporal resolution often face various error sources (e.g., retrieval errors, sampling errors) in their acquisition chain. Addressing uncertainties in a spatiotemporal consistent manner...
Fresh water is a vital natural resource. Earth observation time-series are well suited to monitor corresponding surface dynamics. The DLR-DFD Global WaterPack (GWP) provides daily information on globally distributed inland surface water based on MODIS (Moderate Resolution Imaging Spectroradiometer) images at 250 m spatial resolution. Operating on t...
Observations of changes in terrestrial water storage (TWS) obtained from the satellite mission GRACE (Gravity Recovery and Climate Experiment) have frequently been used for water cycle studies and for the improvement of hydrological models by means of calibration and data assimilation. However, due to a low spatial resolution of the gravity field m...
Locust outbreaks around the world regularly affect vast areas and millions of people. Mapping and monitoring locust habitats, as well as prediction of locust outbreaks is essential to minimize the damage on crops and pasture. In this context, remote sensing has become one of the most important data sources for effective locust management. This revi...
Fresh water is vital for life on the planet. Satellite remote sensing time-series are well suited to monitor global surface water dynamics. The DLR-DFD Global WaterPack (GWP) provides daily information on inland surface water. However, operating on diurnal- and global spatiotemporal resolution comes with certain drawbacks. As the time-series is pri...
The availability of fresh water is vital for life on the planet. However, water resources are increasingly affected by changing patterns of climate variables and intensification of human water use and regulatory management. Consequently, focus of many disciplines is directed towards inland water storage dynamics. Satellite remote sensing offers opp...
Remote sensing time series offer the possibility to monitor surface water at dense temporal intervals. Open data archives as well as developments in cloud computing are the main drivers towards and increased availability of raw data allowing for the extraction of detailed information on water bodies such as natural lakes and artificial reservoirs....
The warming climate is threatening to alter inland water resources on a global scale. Within all waterbody types, lake and river systems are vital not only for natural ecosystems but, also, for human society. Snowmelt phenology is also altered by global warming, and snowmelt is the primary water supply source for many river and lake systems around...
Observations of changes in terrestrial water storage obtained from the satellite mission GRACE (Gravity Recovery and Climate Experiment) have frequently been used for water cycle studies and for the improvement of hydrological models by means of calibration and data assimilation. However, due to a low spatial resolution of the gravity field models...
In China, freshwater is an increasingly scarce resource and wetlands are under great pressure. This study focuses on China’s second largest freshwater lake in the middle reaches of the Yangtze River—the Dongting Lake—and its surrounding wetlands, which are declared a protected Ramsar site. The Dongting Lake area is also a research region of focus w...
This paper is devoted to study the sediment runoff of the Ile River downstream. The article analyses the Kapshagai reservoir impact on regime and characteristics of sediment runoff in the Ile River downstream before and after construction of the reservoir in 1970. Along with the calculation of characteristics of sediment runoff, an assessment of am...
Irrespective of administrative boundaries, river basins are natural spatial units covering the entire land area. They provide many resources, including freshwater, which is essential for the environment and human society, as well as irrigation water and hydropower. At the same time, river basins are highly pressured i.e. by human induced environmen...
Observations of changes in terrestrial water storage obtained from the satellite mission GRACE (Gravity Recovery and Climate Experiment) have frequently been used for water cycle studies and for the improvement of hydrological models by means of calibration and data assimilation. However, due to a low spatial resolution of the gravity field models...
This report constitutes a methods compendium of potential S-1/-2/-3 (S-1/-2/-3) integration strategies aiming at developing and testing integration strategies for S-1, S-2 and coarse resolution optical data to allow benefitting from their complementary multi-resolution, multi-temporal and multi-sensor characteristics. Given the delayed readiness of...
Large-area remote sensing time-series offer unique features for the extensive investigation of our environment. Since various error sources in the acquisition chain of datasets exist, only properly validated results can be of value for research and downstream decision processes. This review presents an overview of validation approaches concerning t...
Globally, the number of dams increased dramatically during the 20th century. As a result, monitoring water levels and storage volume of dam-reservoirs has become essential in order to understand water resource availability amid changing climate and drought patterns. Recent advancements in remote sensing data show great potential for studies pertain...
The Deliverable “D32.1b – Methods Compendium: Time Series Preparation” analyses methods for fully automated pre-processing of Sentinel time series data streams, which are a prerequisite for all further processing tasks. The quality of the pre-processing procedure determines the thematic quality, content, and accuracy that can be achieved in any sub...
The TIMELINE project at the Earth Observation Center (EOC) of the German Aerospace Center (DLR) aims at generating long and homogenized time series of the National Oceanic and Atmospheric Administration (NOAA) and Meteorological Operational Satellite (MetOp) Advanced Very High Resolution Radiometer (AVHRR) data over Europe and North Africa. In the...
The face of our planet is changing at unprecedented speed. Total population grew by 26% between 1992 and 2010, the number of megacities with over 10 million inhabitants more than doubled between 1990 and 2010, and the the latest, uncontestable climate trends, sea level rise, and sporadic endogenous and exogenous natural hazards aggravate environmen...
The seasonal and long-term dynamics of waterbodies, particularly in (semi-)arid and cold regions of the world are strongly dependent on precipitation amounts and temperatures respectively. Even though human influences can also strongly affect the dynamics of such waterbodies, seasonal variabilities and shifts in rainfall or temperature patterns are...
Information on the distribution of inland waters bodies and their seasonal variability is important for supporting water and land management and informed decision making. Furthermore, such data can be crucial basis for scientific analyses in the field of regional and global environmental research. Key functions and services of wetlands for example...
Knowledge about inland surface water distribution and its short- to long-term variability is of high importance. Recently many studies have presented interesting results at regional, continental and global scale with 14.25 m to 25 km spatial and 10 day to one year temporal resolution. However, surface inland water bodies can feature temporally rapi...
West Africa is a hot spot region for land–atmosphere coupling where atmospheric conditions and convective rainfall can strongly depend on surface characteristics. To investigate the effect of natural interannual vegetation changes on the West African monsoon precipitation, we implement satellite-derived dynamical datasets for vegetation fraction (V...
Copernicus is a European Earth Observation (EO) programme headed by the European Commission (EC) in partnership with the European Space Agency (ESA) for the better understanding of the state and changes of our planet. Copernicus provides six operational services on the earth’s main sub-systems (i.e. Land, Atmosphere, Oceans) and on cross-cutting pr...
The assessment of water body dynamics is not only in itself a topic of strong demand, but the presence of water bodies is important information when it comes to the derivation of products such as land surface temperature, leaf area index, or snow/ice cover mapping from satellite data. For the TIMELINE project, which aims to derive such products for...
Biomass is a sensitive indicator of environmental change and ecological functioning. Quantification of biomass is essential to identify and monitor those areas threatened by degradation and desertification. This is especially important in arid and semi-arid environments. However, robust techniques to monitor carbon stocks over large areas and throu...
Water is a scarce resource in many regions of the world. In all Central Asian countries, the society depends on the availability of water either for hydro-power generation or irrigation. Since the collapse of the Soviet Union and the separation into independent countries, water resources management became a critical and political issue. Public info...
Wetlands are rich ecosystems and essential for human life. They provide wildlife habitats, are crucial to agriculture and fishery, purify and store water, and maintain its availability during dry periods. Key functions and services of wetlands are closely related to the temporal variations of water levels and inundation cycles. Daily time series of...
Information on the spatio-temporal dynamics of inland water bodies is of high value for many applications, for example in the context of water and land management or for ecosystem service assessments. In this study, different approaches to delineate inland water bodies from MODIS 250 m time series were compared. Here, the performance of different i...
In many regions of Africa, high population growth rates and the related accelerating need for food, water, energy, and construction materials have led to considerable human impacts on natural resources. Agricultural areas, urban areas, and dispersed rural settlements for example are expanding at the expense of natural forest, grassland, and savanna...
Accurate and timely information on the global cropland extent is critical for food security
monitoring, water management and earth system modeling. Principally, it allows for analyzing
satellite image time-series to assess the crop conditions and permits isolation of the agricultural
component to focus on food security and impacts of various climat...
Accurate and timely information on the global cropland extent is critical for food security monitoring, water management and earth system modeling. Principally, it allows for analyzing satellite image time-series to assess the crop conditions and permits isolation of the agricultural component to focus on food security and impacts of various climat...
The assessment of water body dynamics is not only in itself a topic of strong demand, but the presence of water bodies is important information when it comes to the derivation of products such as land surface temperature, leaf area index, or snow/ice cover mapping from satellite data. For the TIMELINE project which aims to derive such products for...
River deltas belong to the most densely settled places on earth. Although they only account for 5% of the global land surface, over 550 million people live in deltas. These preferred livelihood locations, which feature flat terrain, fertile alluvial soils, access to fluvial and marine resources, a rich wetland biodiversity and other advantages are,...
Natural lakes, lakes under strong anthropogenic influence and artificial reservoirs feature strong intra- and interannual variability in their surface extent. The variability reflects meteorological and environmental conditions as well as human impact. Knowledge of spatio-temporal patterns of such inland water bodies is crucial for many reasons. Si...
The understanding and assessment of surface water variability of inland water bodies,
for example, due to climate variability and human impact, requires steady and continuous
information about its inter- and intra-annual dynamics. In this letter, we present
an approach using dynamic threshold techniques and utilizing time series to generate a
data...
The knowledge and understanding of intra- and inter annual characteristics of inland water bodies, such as natural lakes and artificial reservoirs are crucial for many reasons. Inland water bodies are sensitive to environmental variations and human impact which is reflected in spatial and temporal dynamics of surface extent. A time-series of areal...
Water is a scarce resource in many regions of the world. In all Central Asian countries, the society depends on the availability of water either for hydro-power generation or irrigation. Since the collapse of the Soviet Union and the separation into independent countries, water management became a political issue. Public information on water resour...
Human activity and climate variability has always changed the Earth’s
surface and both will mainly contribute to future alteration in land cover and land
use changes. In this chapter we demonstrate a land cover and land use classification
approach for Central Asia addressing regional characteristics of the study
area. With the aim of regional class...
Arid and semiarid environments are susceptible to environmental degradation and desertification.
Modelling net primary productivity (NPP) and analysis of spatio-temporal patterns help to understand
ecological functioning especially in these areas. In this study, we apply the Biosphere Energy Transfer
Hydrology Model (BETHY/DLR) to derive NPP for Ka...
Monitoring of net primary productivity (NPP) is especially important for the fragile ecosystems in arid and semi-arid regions. Great interest exists in observing large-scale vegetation dynamics and understanding spatial and temporal patterns of NPP in these areas. In this study we present results of NPP obtained with the model BETHY/DLR for Kazakhs...
Based on NOAA/AVHRR NDVI biweekly time-series data, the start and end of the growing season of Central Asia from 1982 to 2006 were estimated. Trend analysis results indicate an earlier green-up and a later dormancy over the entire area during the study period. For seven main vegetation types, the largest advance of greenup onset (0.597 days/year) o...
Monitoring of net primary productivity (NPP) is especially important for the fragile ecosystems in arid and semi-arid regions. Great interest exists in observing large-scale vegetation dynamics and understanding spatial and temporal patterns of NPP in these areas. In this study we present results of NPP obtained with the model BETHY/DLR for Kazakhs...