An Analysis on Spatial—Temporal Distribution of Rainfall Erosivity in Guizhou Province

Rainfall is the main dynamic factor that causes soil loss and rainfall erosivity, it shows the potential ability of the soil loss caused by rainfall. Estimating the rainfall erosivity accurately is significant to predict soil loss quantitatively and make soil and water conservation program. Guizhou Province, with serious soil erosion, is one of the typical regions whose ecological environment is very fragile. In order to estimate rainfall erosivity accurately and analyze the spatial distribution and temporal change of rainfall erosivity, a daily rainfall erosivity model was adopted to calculate the rainfall erosivity of Guizhou Province using daily rainfall data during 1951—2001 from 19 weather stations. The results indicate that rainfall erosivity show increasing trend during the last 50 years which indicates that the potential ability of the soil loss caused by rainfall increase in Guizhou Province. The seasonal distribution of annual average rainfall erosivity is centralized and the percentage of rainfall erosivity in summer is 68.48%.The spatial distribution of rainfall erosivity shows decreasing trend from the south to the north. The center with the largest rainfall erosivity is located in the southwest and southeast regions in Guizhou Province, while the center with the smallest rainfall erosivity is located in the northwest regions. However, rainfall erosivity is influenced by rainfall amount and intensity, there are a lot of differences between the distribution of rainfall and rainfall erosivity. According to the seasonal changing character of rainfall erosivity of whether stations, three regions are classified in Guizhou Province. With the increase of longitude from the west to the east regions, the centralization degree in seasonal distribution of annual rainfall erosivity decreases.