Multiseasonal, multifrequency, multipolarization, and multiresolution radar speckle and feature tracking for Arctic glacier velocities

-

Glacier flow is a fundamental Earth surface process. Connecting ice accumulation and ablation, it is an integral element of glacier systems and their response to climate and its changes. Quantification of ice velocities on glaciers is a crucial step towar ds (i) understanding and modeling of the dynamic processes involved, (ii) estimating the system responses to external forcing, such as changes in climatic conditions, and (iii) assessing related impacts. With the Arctic being a region presently particular ly affected by atmospheric warming, monitoring of Arctic glaciers is of critical importance for understanding regional climate change and its impacts, such as sea level contribution. In particular on Svalbard with its high percentage of surge-type glacier s, knowledge of spatio-temporal glacier flow is crucial for interpreting observed glacier volume changes correctly. Radar satellite sensors with their all-weather and night-time capability are the only means to continuously monitor glacier flow in polar e nvironments. While the motion of slow-moving glaciers can in theory be derived through synthetic aperture radar (SAR) interferometry, fast-flowing glaciers have to be measured using correlation between repeat data (offset tracking). The present project RA STAR will explore the dependency of trackable SAR backscatter features from different seasons and weather conditions, different radar bands (L, C, X), and different SAR polarizations and spatial resolutions, focusing in particular on new and upcoming sens ors like TerraSAR-X, RADARSAT-2 or ESA Sentinel-1. The findings will be compiled to an integral methodology and observation strategy. From that, the first multitemporal glacier velocity map over entire Svalbard will be produced and the results be analysed towards Svalbard calving flux, surge activities, and velocity trends over time. The map will further be a key to understand current and forthcoming (ESA CRYOSAT-2) elevation change data over Svalbard.