HR: 14:05h
AN: H23F-02    [Abstracts]
TI: An Off-Line Intercomparison of Soil Moisture Simulation by AOGCMs
AU: * Cornwell, A R
EM: cornwella@geog.utoronto.ca
AF: Department of Geography, University of Toronto, 100 St. George Street, Toronto, ON M5S3G3 Canada
AU: Harvey, L D
EM: harvey@geog.utoronto.ca
AF: Department of Geography, University of Toronto, 100 St. George Street, Toronto, ON M5S3G3 Canada
AB: Atmosphere-ocean general circulation models (AOGCMs) employ very different land surface schemes (LSSs) and as a result their predictions of land surface quantities such as soil moisture are often difficult to compare. Some of the disagreement in their results is likely due to differences in the atmospheric component; however, previous intercomparison studies have determined that different LSSs can produce very different results even when supplied with identical atmospheric forcing. A simple off-line LSS is presented that can reproduce the soil moisture simulations of various AOGCMs, based on their modeled temperature and precipitation. The scheme makes use of the well-established Thornthwaite method for estimating potential evapotranspiration combined with a variation of the Manabe `bucket' model. The model can be tuned to reproduce the control climate soil moisture of an AOGCM by adjusting the ease with which runoff and evapotranspiration continue as the moisture level in the bucket goes down. This produces a set of parameter values that can provide a reasonably good fit to each of several AOGCM control climates. As well, the parameter values can be set to imitate the LSS from one AOGCM while the model is forced with atmospheric data from another, providing an estimate of the magnitude of variation caused by the differences in land surface parameterization.
DE: 3322 Land/atmosphere interactions
DE: 3337 Numerical modeling and data assimilation
DE: 3309 Climatology (1620)
DE: 1833 Hydroclimatology
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting