A COMPARISON OF SIMPLE AND COMPLEX TREATMENTS OF SURFACE HYDROLOGY AND THERMODYNAMICS SUITABLE FOR MESOSCALE ATMOSPHERIC MODELS

Citation
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
Citations number
31
Categorie Soggetti
Metereology & Atmospheric Sciences
Journal title
ISSN journal
00270644
Volume
122
Issue
5
Year of publication
1994
Pages
880 - 896
Database
ISI
SICI code
0027-0644(1994)122:5<880:ACOSAC>2.0.ZU;2-R
Abstract
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.