Abstract: The phenomenon of the Karst desertification not only impacts the ecological environment but also alter the distribution of agriculturalmeteorology factors. Regional climate model (RegCM3) was applied to explore the possible effects of land use changes on local and regional climate over the Karst desertification area in Guizhou. With the resolution of 20km×20km, two numerical simulation experiments were conducted. One was a control experiment with more vegetation land use and the other is the desertification in 2000. Preliminary analysis indicated that the desertification over the area of Guizhou caused different climate effects in different regions and seasons. In the most parts of the desertification area the month precipitation decreased from 20mm to 80mm, and it increased in some other area. In summer and autumn, surface air temperatures increased obviously in the area of the Karst desertification. 〖JP2〗In dry season the relative humidity decreased about 2%～8%,but did not change obviously in rainy season in the desertification area. The evapotranspiration reduced a little, and the evaporation increased distinctly in summer in the desertification area.

Key words: RegCM3, Karst desertification, Numerical simulation, Regional climate