Catchment Land Surface Model
Entry ID: NASA_CATCHMENT_LSM
Abstract: The one-dimensional framework used by traditional one-dimensional LSMs
(including the Mosaic LSM) is not amenable to an adequate treatment of runoff
generation or subsurface soil moisture movement, since both processes in nature
are largely controlled by spatial heterogeneity in soil moisture. Consider, for
example, that many LSMs coupled to AGCMs effectively consider soil ... moisture to
be spatially uniform in thin soil layers (in some cases a few centimeters
thick) that span hundreds of kilometers! Calculations of soil moisture
transport between these massively extensive but very thin layers are then
computed with precise equations developed for use at the point scale. Needless
to say, nature does not work this way.
This deficiency suggests a logical development path, namely, an improved
treatment of the subgrid horizontal structure of land surface hydrological
processes. The development of the NSIPP Catchment LSM is an attempt to follow
this path. In this LSM, subgrid heterogeneity in surface moisture state is
treated statistically, since computational constraints (now and in the
foreseeable future) prevent it s explicit resolution. Nevertheless, the applied
distributions are related sensibly to the topography, which exerts a major
control over much of the subgrid variability.
[Summary provided by NASA.]
ISO Topic Category
Koster, R. D., M. J. Suarez, A. Ducharne, M. Stieglitz, and P. Kumar, A
catchment-based approach to modeling land surface processes in a GCM, Part 1,
Model Structure, J. Geophys. Res., 105, 24809-24822, 2000.
Ducharne, A., R. D. Koster, M. J. Suarez, M. Stieglitz, and P. Kumar, A
catchment-based approach to modeling land surface processes in a GCM, Part 2,
Parameter estimation and model demonstration, J. Geophys. Res., 105,
Stieglitz, M., A. Ducharne, R. D. Koster, and M. J. Suarez, The impact of
detailed snow physics on the simulation of snow cover and subsurface
thermodynamics at continental scales, J. Hydromet., in press.
Creation and Review Dates