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Land-Surface Model

We use a single land-surface layer


where tex2html_wrap_inline2532 is a land heat capacity; since this is small, on time scales much longer than a day the condition is essentially zero net surface flux.

Evaporation over land is modified as


where tex2html_wrap_inline2536 is the aerodynamic resistance; tex2html_wrap_inline2538 is similar to the a combined stomatal and root resistance (Dickinson 1984), and increases as the soil wetness w drops. Evaporation thus becomes less dependent on wind speed and roughness for low soil moisture, akin to biophysical models.

For interactive soil wetness, we use a single layer formulation representing the root zone


with P the precipitation and R the runoff.

Johnny Wei-Bing Lin
Wed Aug 26 16:58:31 PDT 1998