NCAR Land Surface Model (NCAR LSM version 1)

Background

Land-atmosphere interactions have traditionally been described in terms of four sub-disciplines: biogeophysical fluxes, biogeochemical fluxes, hydrology, and ecosystem dynamics. However, many ecological, hydrological, and atmospheric processes are so intertwined that these cannot be considered separate disciplines. Successful modeling of net primary production, carbon storage, and trace gas emissions (e.g., methane, non-methane hydrocarbons, nitrous oxide) requires an accurate model of the micrometeorological and hydrological environments in addition to the traditional ecological emphasis on vegetation and biogeochemical controls. Successful modeling of latent and sensible heat fluxes requires an accurate description of the ecological state and biogeochemical controls in addition to the traditional emphasis on the physical environment.

More importantly, many ecological, hydrologic, biogeochemical, and atmospheric models parameterize the same processes though with vastly different time-scales and complexity. This introduces internal self-consistency problems when coupling component models into a comprehensive land-atmosphere model. See

for a discussion of some of the important issues.

In the late-1980's, I became interested in combining the relevant biogeophysical, biogeochemical, hydrologic, and ecosystem processes into a comprehensive model of land-atmosphere interactions that was physically and biologically realistic and also internally self-consistent. The primary motivation for this work was to study land-atmosphere CO2 exchange in boreal forests. This early work directly lead to the development of a more generalized land surface model for coupling to atmospheric general circulation models.


Copyright (c) 1996



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