Spaceborne remote sensing for snow hydrology applications

Certain satellite-based remote sensing for snow hydrology applications has been very positive, namely, snow areal extent mapping using visible and near-infrared sensors and snow water equivalent using passive microwave techniques. Although certain problems are yet to be solved, very specific applications have become operational. Data from the NOAA-AVHRR sensor are used to produce snow extent maps for about 4000 basins in North America and the data are distributed electronically by the NWS National Operational Hydrologic Remote Sensing Center. At the Canadian Climate Centre, a method has been developed for real time estimation of areal snow water equivalent over the Canadian prairies using microwave brightness temperatures, and the snow water equivalent maps are distributed to operational hydrological forecasters. Current research may also prove fruitful for estimates of snow wetness or active melting, snow albedo and snow grain size. It appears that forthcoming improvements in passive microwave spatial resolution should increase the applicability of the data for snow hydrology. The spectral and spatial resolution of the visible/near-infrared data will also be improved with the launch of EOS/MODIS. Combinations of sensors and integration with other types of data will further improve the suitability of spaceborne data.