TY - JOUR A1 - Kaiser, Soraya A1 - Grosse, Guido A1 - Boike, Julia A1 - Langer, Moritz T1 - Monitoring the transformation of Arctic landscapes BT - automated shoreline change detection of lakes using very high resolution imagery JF - Remote sensing / Molecular Diversity Preservation International (MDPI) N2 - Water bodies are a highly abundant feature of Arctic permafrost ecosystems and strongly influence their hydrology, ecology and biogeochemical cycling. While very high resolution satellite images enable detailed mapping of these water bodies, the increasing availability and abundance of this imagery calls for fast, reliable and automatized monitoring. This technical work presents a largely automated and scalable workflow that removes image noise, detects water bodies, removes potential misclassifications from infrastructural features, derives lake shoreline geometries and retrieves their movement rate and direction on the basis of ortho-ready very high resolution satellite imagery from Arctic permafrost lowlands. We applied this workflow to typical Arctic lake areas on the Alaska North Slope and achieved a successful and fast detection of water bodies. We derived representative values for shoreline movement rates ranging from 0.40-0.56 m yr(-1) for lake sizes of 0.10 ha-23.04 ha. The approach also gives an insight into seasonal water level changes. Based on an extensive quantification of error sources, we discuss how the results of the automated workflow can be further enhanced by incorporating additional information on weather conditions and image metadata and by improving the input database. The workflow is suitable for the seasonal to annual monitoring of lake changes on a sub-meter scale in the study areas in northern Alaska and can readily be scaled for application across larger regions within certain accuracy limitations. KW - change detection KW - shoreline movement rate KW - shoreline movement direction KW - arctic water bodies KW - permafrost lowlands KW - automated monitoring KW - North KW - Slope KW - very high resolution imagery Y1 - 2021 U6 - https://doi.org/10.3390/rs13142802 SN - 2072-4292 VL - 13 IS - 14 PB - MDPI CY - Basel ER - TY - JOUR A1 - Milewski, Robert A1 - Chabrillat, Sabine A1 - Behling, Robert T1 - Analyses of Recent Sediment Surface Dynamic of a Namibian Kalahari Salt Pan Based on Multitemporal Landsat and Hyperspectral Hyperion Data JF - Remote Sensing N2 - This study combines spaceborne multitemporal and hyperspectral data to analyze the spatial distribution of surface evaporite minerals and changes in a semi-arid depositional environment associated with episodic flooding events, the Omongwa salt pan (Kalahari, Namibia). The dynamic of the surface crust is evaluated by a change-detection approach using the Iterative-reweighted Multivariate Alteration Detection (IR-MAD) based on the Landsat archive imagery from 1984 to 2015. The results show that the salt pan is a highly dynamic and heterogeneous landform. A change gradient is observed from very stable pan border to a highly dynamic central pan. On the basis of hyperspectral EO-1 Hyperion images, the current distribution of surface evaporite minerals is characterized using Spectral Mixture Analysis (SMA). Assessment of field and image endmembers revealed that the pan surface can be categorized into three major crust types based on diagnostic absorption features and mineralogical ground truth data. The mineralogical crust types are related to different zones of surface change as well as pan morphology that influences brine flow during the pan inundation and desiccation cycles. These combined information are used to spatially map depositional environments where the more dynamic halite crust concentrates in lower areas although stable gypsum and calcite/sepiolite crusts appear in higher elevated areas. KW - salt pan KW - playa KW - hyperspectral KW - multitemporal KW - change detection KW - evaporite minerals Y1 - 2016 U6 - https://doi.org/10.3390/rs9020170 SN - 2072-4292 VL - 9 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Korzeniowska, Karolina A1 - Korup, Oliver T1 - Object-Based Detection of Lakes Prone to Seasonal Ice Cover on the Tibetan Plateau JF - Remote sensing KW - Tibetan Plateau KW - lakes KW - LANDSAT KW - SRTM KW - MNDWI KW - OBIA KW - change detection Y1 - 2017 U6 - https://doi.org/10.3390/rs9040339 SN - 2072-4292 VL - 9 PB - MDPI CY - Basel ER -