Challenges and Solutions to High Resolution Soil Moisture Mapping
Jeffrey P. Walker and Paul R. Houser
Power Point Presentation
Information about soil moisture is of critical importance to real-world applications such as agriculture, water resource management, flood and fire prediction, military mobility, insurance agencies, etc. Moreover, many of these applications require soil moisture information at high resolution. While this may be estimated from land surface models, the predictions are often poor due to poor model physics, parameter estimates and atmospheric forcing data. Alternatively, remote sensing satellites may be used but they only give a soil moisture estimate for the top few centimetres. Moreover, the sensors that give the most reliable soil moisture estimates (passive microwave) have relatively low resolution, being on order 50km. Such sensors include the Advanced Microwave Scanning Radiometer for EOS (AMSR-E), a non-ideal sensor configuration, and two missions expected before the end of the decade targeted at measuring near-surface soil moisture with ideal sensor configuration; the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) mission, and the National Aeronautics and Space Administration (NASA) Hydrospheric states "Hydros" mission. Other high resolution satellite observations have been shown to contain information on soil moisture, but this data (active microwave, visible and thermal) is noisy and/or difficult to interpret. However, it may be possible to downscale the accurate low resolution passive microwave data using the noisy high resolution data and/or modelling. In fact, Hydros proposes to provide a better than 10km resolution soil moisture product by merging 3km active microwave data with 40km passive microwave data. This paper presents some examples of how high resolution soil moisture data may be obtained from active-passive soil moisture retrieval, visible/thermal downscaling, and assimilation into a high resolution land surface model.