Mn. Lakhtakia et Tt. Warner, A COMPARISON OF SIMPLE AND COMPLEX TREATMENTS OF SURFACE HYDROLOGY AND THERMODYNAMICS SUITABLE FOR MESOSCALE ATMOSPHERIC MODELS, Monthly weather review, 122(5), 1994, pp. 880-896
Alternative treatments of the hydrologic and thermodynamic processes a
t the earth's surface within a mesoscale model are discussed in this s
tudy. Specifically, the question of under what circumstances it is nec
essary to use a complex surface parameterization scheme as opposed to
simpler ones is addressed. Three versions of a one-dimensional planeta
ry boundary layer model were employed, where the primary differences a
mong them are in their surface modules. One uses a simple treatment of
the surface characteristics (time independent). In another, the surfa
ce processes are represented by a complex surface physics-soil hydrolo
gy scheme, while the third one is similar to the first one but the moi
sture-availability parameter has a specified temporal variation during
and after a precipitation event. Several numerical simulations were p
erformed. They showed that the models' solutions differ the most when
the vegetation cover and the surface net radiative flux are large, and
the soil-water content cannot satisfy the evapotranspiration demand.
When a precipitation event is present during the simulation period, th
e largest differences are apparent when the preprecipitation surface e
vapotranspiration is restricted and the precipitation event occurs in
the morning. The simulations also showed that the upgraded simple sche
me can sometimes represent a satisfactory substitute for the simple sc
heme when a precipitation event is present during the simulation perio
d.