Precipitation Variation and Its Impacts in Sichuan in the Last 50 Years

Based on the daily precipitation data of 133 stations in Sichuan from 1961 to 2008, precipitation variation and its impacts are analyzed in this paper. Results indicate that during 1961-2008, the spatial distribution of the annual precipitation variation in Sichuan shows an increase-decrease-increase situation from west to east: increase in most parts of Ganzi and Liangshan, decrease in Aba and most parts of Sichuan Basin and increase in the northeastern part of the basin. The linear trend coefficient field in the spatial changes of the rainstorm days also displays an increase-decrease-increase situation from west to east: increase in most parts of Ganzi, Liangshan and Panzhihua, remarkable decrease in the western and central parts of the basin and significant increase in the northeastern part of the basin. Apart from some parts of the central and southern basin, the rainstorm intensity in the province tended to increase, and the trend in the northeastern part of the basin was notable. The variation trend of the heavy rain days is close to that of the rainstorm, showing an increase-decrease-increase change from west to east. Except for some parts of Ganzi, the number of moderate and light rain days in most parts of Sichuan decreased. On the contrary, the number of days without rain increased greatly in most parts of the province, except for part of western Sichuan Plateau.