HR: 14:40h
AN: H12F-05    [PDF]
TI: Precipitation and Radiation Forcings in Off-line Assimilation of Soil Moisture
AU: * Belair, S
EM: stephane.belair@ec.gc.ca
AF: Meteorological Service of Canada, 2121 Trans-Canada N., Suite 500, Dorval, Que H9P1J3 Canada
AB: In order to facilitate the eventual inclusion of space-based remote sensing data in operational soil moisture assimilation, an off-line surface assimilation system is currently being developped at the Meteorological Service of Canada (MSC). In this new system, our best estimates for atmospheric forcings, i.e., precipitation, downwelling radiation (solar and infrared), low-level air temperature, humidity, and winds, are used to drive the Interactions Soil-Biosphere-Atmosphere (ISBA) land surface scheme. The behavior of this new system was compared with the strategy currently used operationally at MSC, which is based on a statistical interpolation that relate model-errors on low-level air temperature and relative humidity to errors in soil moisture. Results show that improving precipitation forcings (obtained from NEXRAD Level III data) slightly alters the evolution of soil moisture, with non-negligeable impacts on 2-m air temperature and relative humidity. Another sensitivity experiment indicates that, at least for the case examined in this study, reasonably large changes to downwelling solar radiation did not modify much the evolution of soil moisture, but had a significant impact on low-level air characteristics. The implications of these results for future soil moisture assimilation will be discussed at the conference.
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2003 Fall Meeting