REMOTE-SENSING CONTRIBUTION TO LAND SURFACE HYDROLOGY

Over the last decade, the importance of the global hydrological cycle has become increasingly clear in understanding global processes. Furthermore, the utility of spaceborne observations for global studies has been better demonstrated. Optical sensors such as the NOAA AVHRR and the Landsat or SPOT sensors, for example, have been demonstrated to provide land cover information describing the dynamics of vegetation and snow cover over a variety of spatial and temporal scales. Microwave observations from the synthetic aperture radars and passive microwave radiometers such as the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) have been shown to effectively observe snowpack properties, vegetation condition, biomass volume, and condition and indices of soil wetness. The Earth Observing System (EOS) mission plus complementary missions such as ERS-1, the Japanese ERS-1, and the Tropical Rainfall Measuring Mission (TRMM) offer the potential to extend and improve presently available observations from space so more knowledge and understanding of the global hydrological cycle will be obtained.