Challenges and Achievements in Circumpolar Monitoring of Land Surface Hydrology with Satellite Data

Abstract:

Land surface hydrology related features in arctic and sub-arctic environments which can be detected with satellite data include open water, near surface soil water storage, snow and freeze/thaw state. Their circumpolar spatial and temporal patterns are important for the understanding of land atmosphere exchange and changes in ground thermal properties. Datasets based on remotely sensed data are frequently used to evaluate climate models or to conduct trend analyses with respect to climate change. Although many circumpolar to global datasets are available, their applicability is often limited. A major challenge is the abundance of small lakes. This includes their impact on coarse resolution global products accuracy as well as their detection itself. Many studies have shown that the extent of the majority of tundra lakes is below the resolution of to date available global land cover datasets. An often followed strategy is to mosaic datasets from several months to years in order to overcome the problem of cloud coverage before application of long term change detection. However, many lakes vary seasonally in size. It can be shown that inundation patterns (with respect to lakes) are not limited to spring time by use of synthetic aperture radar (SAR). In addition seasonal changes of aquatic vegetation extent needs to be considered. This has been quantified over the Yamal region and a range of further sites (including PAGE21 sites, www.page21.eu) in Siberia.