TY  - JOUR
A1  - Arendt, Robert
A1  - Reinhardt-Imjela, Christian
A1  - Schulte, Achim
A1  - Faulstich, Leona
A1  - Ullmann, Tobias
A1  - Beck, Lorenz
A1  - Martinis, Sandro
A1  - Johannes, Petrina
A1  - Lengricht, Joachim
T1  - Natural pans as an important surface water resource in the Cuvelai Basin — Metrics for storage volume calculations and identification of potential augmentation sites
JF  - Water
N2  - 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.
KW  - Namibia
KW  - Angola
KW  - Oshana
KW  - flood
KW  - drought
KW  - water retention
KW  - storage volume
KW  - Blue Spot Analysis
KW  - TanDEM-X
KW  - pan
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223019
SN  - 2073-4441
VL  - 13
IS  - 2
ER  - 
TY  - JOUR
A1  - Abdullahi, Sahra
A1  - Wessel, Birgit
A1  - Huber, Martin
A1  - Wendleder, Anna
A1  - Roth, Achim
A1  - Kuenzer, Claudia
T1  - Estimating penetration-related X-band InSAR elevation bias: a study over the Greenland ice sheet
JF  - Remote Sensing
N2  - Accelerating melt on the Greenland ice sheet leads to dramatic changes at a global scale. Especially in the last decades, not only the monitoring, but also the quantification of these changes has gained considerably in importance. In this context, Interferometric Synthetic Aperture Radar (InSAR) systems complement existing data sources by their capability to acquire 3D information at high spatial resolution over large areas independent of weather conditions and illumination. However, penetration of the SAR signals into the snow and ice surface leads to a bias in measured height, which has to be corrected to obtain accurate elevation data. Therefore, this study purposes an easy transferable pixel-based approach for X-band penetration-related elevation bias estimation based on single-pass interferometric coherence and backscatter intensity which was performed at two test sites on the Northern Greenland ice sheet. In particular, the penetration bias was estimated using a multiple linear regression model based on TanDEM-X InSAR data and IceBridge laser-altimeter measurements to correct TanDEM-X Digital Elevation Model (DEM) scenes. Validation efforts yielded good agreement between observations and estimations with a coefficient of determination of R\(^2\) = 68% and an RMSE of 0.68 m. Furthermore, the study demonstrates the benefits of X-band penetration bias estimation within the application context of ice sheet elevation change detection.
KW  - InSAR height
KW  - penetration bias
KW  - cryosphere
KW  - TanDEM-X
KW  - Greenland ice sheet
KW  - DEM
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193902
SN  - 2072-4292
VL  - 11
IS  - 24
ER  -