Combined active and passive microwave remote sensing of snow in Finland

We examined the use of data from active (QuikScat on SeaWinds) and passive (SSM/I on DMSP) space-borne microwave sensors for monitoring key snow parameters in Finland. The feasibility of these data for the task was determined both separately and using a combined data set. The results are based on satellite and ground truth data for 21 test sites in Finland covering the winters of 1999-2000, 2000-2001, and 2001-2002. We show that a Ku-band scatterometer with a fixed incidence angle provides reasonable accuracy for retrieval of dry snow water equivalent (SWE). Using the combined active/passive data set retrieval accuracy is better than with SSM/I data. QuikScat data can also be used for determining onset of snow melting and snow-covered area (SCA) in spring.