GFZ German research centre for geo sciences

Signals of Climate and Landscape Change preserved in Southern African GeoArchives

Funding by: Bundesministerium für Bildung und Forschung (BMBF)
Funding ID: Grant agreement No 03G0838B
Project executing or management agency: Projektträger Jülich (PtJ)
Funding period: 01. Juli 2013 – 30. Juni 2016
Project partners: Technische Universität München (TUM) I Senckenberg am Meer Wilhelmshaven (SaM) I Universität Oldenburg I Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum (GFZ)

Sediment archives provide major sources for the reconstruction of past environmental changes, as they have been permanently modified by alternating process regimes due to climatic fluctuations and recent anthropogenic impacts. The remote sensing based approach in the SPACES GeoArchive will demonstrate the potential and constraints of applied hyperspectral remote sensing imagery with its extended spectral coverage and high spectral resolution for the problem of the identification and mapping of sediment features associated with palaeoenvironmental archives and process analyses in the Southern African region. Particularly, the projects aims at the interpretation of different sediment facies delivers type, direction, or intensities of alternating processes of fluvial, lacustrine and aeolian sedimentary archives. High-resolution geoarchives of interest have been identified that were created within the time span of the most recent decades and centuries. Hyperspectral and multispectral remote sensing imagery at local and regional scale will be used to directly and indirectly analyse landscape features, their formation and dynamic in these semi-arid to arid region based on geochemical and physical parameters. In the context of global change, this project aims at developing the support of recent and upcoming Earth Observation Tools for the study of climate and land use changes impacts on the landscape ecosystem, and contribute with our results for the definition of better sustainable Earth-System management strategies in the future.

The remote sensing section at GFZ is in particular head of the sub-project 1 (SP1): Identification and mapping of palaeoenvironmental archives and process analysis in Southern Africa based on hyperspectral and multispectral remote sensing technology. Our work focused on the combination of advanced methods in optical remote sensing integrating newly available multispectral time-series with rare hyperspectral satellite imagery for the mapping and monitoring of surface changes and crust developments over the Omongwa salt pan in the Namibian Kalahari region (Milewski et al., 2017, 2020). The results show that the crust dynamics are mainly driven by flooding events in the wet season, but are also influenced by temperature and aeolian activity in the dry season. The approach utilized combines the advantages of multitemporal satellite data for temporal event characterization with advantages from hyperspectral methods for the image and ground data analyses that allow improved mineralogical differentiation and characterization. Further, a new method for the quantification of gypsum content in surface sediments was developed (Milewski et al., 2019).

Publications

Milewski, R. (2020): Potential of Optical Remote Sensing for the Analysis of Salt Pan Environments. Dissertation Universität Potsdam.

Milewski, R., Chabrillat, S. and Bookhagen, B. (2020), Analyses of Seasonal Salt Pan Crust Dynamic and their Climatic Drivers using Landsat 8 Time-Series and Ground Data, Remote Sensing, 12: 474. DOI

Milewski, R., Chabrillat, S., Brell, M., Schleicher, A. and Guanter, L. (2019), Assessment of the 1.75 µm Absorption Feature for Gypsum Estimation Using Laboratory, Air- and Spaceborne Hyperspectral Sensors, International Journal of Applied Earth Observation and Geoinformation, 77: 69-83 DOI

Behling, R., Milewski, R. and Chabrillat, S. (2018), Spatiotemporal shoreline dynamics of Namibian coastal lagoons derived by a dense remote sensing time series approach, International Journal of Applied Earth Observation and Geoinformation, 68: 262–271. DOI 

Milewski, R., Chabrillat, S. and Behling, R. (2017), Analyses of Recent Sediment Surface Dynamic of a Namibian Kalahari Salt Pan Based on Multitemporal Landsat and Hyperspectral Hyperion Data, Remote Sensing, 9: 170.  DOI

Wilkes, H., Bens, O., Chabrillat, S., Mangelsdorf, K., Völkel, J., Wagner, D. And Wehrmann, A. (2014): Landschaftsentwicklung und Klimawandel im Südlichen Afrika, System Erde 4, 2: 38-45. DOI

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