Scaling and Assimilation of Soil Moisture and Streamflow (SASMAS): Project Overview and Preliminary Results
Manju Hemakumara, Christoph Ruediger, Barry Jacobs, Jetse Kalma, Jeffrey Walker, Garry Willgoose, Greg Hancock and Patricia Saco
The aim of the SASMAS research project is to provide meaningful estimates of spatial distribution and temporal variation of soil moisture content in the root zone through a combination of modelling and observations using data assimilation. The field work component includes the validation of remotely sensed Advanced Microwave Scanning Radiometer for the Earth observing system (AMSR-E), near-surface soil moisture data (25km x 25km spatial resolution), collection of near-surface soil moisture and stream flow data for assimilation, and monitoring of point soil moisture profiles for validation purposes. The monitoring includes 26 soil moisture profile monitoring sites, 9 stream gauges, 5 weather stations, and numerous rain gauges throughout the 7 000 km2 Goulburn River catchment in NSW, Australia. Monitoring is concentrated in the northern more open cropping and grazing half of the catchment, with less intensive monitoring in the southern more forested half of the catchment. The “scaling” component of this research is developing techniques for downscaling the large-scale satellite measurements to the point-scale, while the “soil moisture assimilation” component is investigating the best way to use both the large- and point- scale near-surface soil moisture data to better estimate the root zone soil moisture content in areas of low vegetation. The “streamflow assimilation” component is investigating how streamflow data may be used to better estimate the root zone soil moisture content in areas of dense vegetation (where remote sensing data is not available), and how it may be used to further constrain soil moisture estimates in areas of low vegetation. In this paper we will provide an overview of the SASMAS project and its research objectives and we will present preliminary results of groundbased monitoring and recent large-scale AMSR-E validation experiments.