This data portal enables accessing a monitoring system for area-wide flow-velocity fields of the outlet glaciers of the Greenland ice sheet. For this, the freely available Landsat archive is exploited. For the time span 1972–2015 more than 200,000 flow-velocity fields were derived from more than 37,000 optical multi-sensoral Landsat scenes (Landsat 1 to Landsat 8). Thus, this monitoring system provides both a high temporal densification and a remarkable extension of existing flow-velocity information along the margin of the Greenland ice sheet.



In order to process the large amount of satellite images an almost automated monitoring system was developed. The processing includes a number of steps that are described in detail by Rosenau et al. (2015). The orthorectification was improved utilizing the Global Digital Elevation Map V2 (GDEM-V2) of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER).A destriping correction was applied for Landsat 7 products that exhibit the scan line corrector (SLC) failure.

In addition, outliers were removed using an adaptive, recursive filter approach. The combination of all improvements leads to a higher accuracy of the inferred velocity fields.



The long time span covered allows determining long-term flow-velocity trends. The high temporal resolution facilitates the analysis of seasonal flow-velocity variations of numerous outlet glaciers. In the analyses an acceleration pattern could be detected for many outlet glaciers. These findings are consistent with most of previously published analyses. However, the temporal and spatial distribution of the flow-velocity changes do not show a uniform pattern.



Rosenau, R.; Scheinert, M.; Dietrich, R. (2015): A processing system to monitor Greenland outlet glacier velocity variations at decadal and seasonal time scales utilizing the Landsat imagery. Remote Sens. Environ., 169, 1-19, doi: 10.1016/j.rse.2015.07.012