COMPARISON AND ANALYSIS OF SEVERAL PLANETARY BOUNDARY LAYER SCHEMES IN WRF MODEL BETWEEN CLEAR AND OVERCAST DAYS

In the present study, several most commonly used planetary boundary layer (PBL) parameterization schemes in the WRF model are utilized together with the observational data at Shouxian (from August to December, 2008). The present work is a part of Atmospheric Radiation Measurement (ARM) facility supported by the U.S. Department of Energy installed at Shouxian in China. In this study, we compared the simulation effect of meteorological elements and the structure of PBL over typical farmlands underlying surface from different parameterization schemes between clear and overcast days. The observational results revealed that for the simulation of cloud status, non-local schemes such as ACM2 and YSU are superior to the local schemes. Further, the ACM2 scheme is better in simulating temperature and vapor at a height of 2 m from the surface, and the MYJ scheme has an advantage over other schemes when simulating the wind direction or its speed. Also, for the simulation of potential temperature and vapor profile, non-local schemes (ACM2 and YSU) are superior to the local schemes both during clear and overcast days. It is depicted that the ACM2 scheme has better advantages when simulating under weak stable conditions and humidity inversion structure during night time. Moreover, for the simulation of wind speed profile, the MYJ and MYNN2.5 schemes are the best respectively during the clear and overcast days, under unstable day time condition. However, when considering weak stable condition, ACM2 scheme has a minimum deviation on clear days and YSU scheme is the best choice on overcast days. From the overall results, ACM2 scheme is superior both on clear and overcast days, when simulation is based on typical farmland underlying surface.