Spatial and Temporal Distribution and Variation Characteristics of Rainfall in Guizhou Province in Recent 50 Years
Based on the monthly precipitation data of 19 meteorological stations from 1960 to 2009 in Guizhou province,the methods,such as precipitation concentration index (PCI),climate tendency coefficient,Mann-kendall test,sliding T-test and wavelet analysis,were employed to analyze temporal and spatial variation of precipitation in different time scales.The results show that the spatial distribution of annual rainfall is very uneven.Rainfall distribution increased gradually from west to east while the formation of three precipitation abundant places and three precipitation poor places.Annual precipitation appeared downward trend during the recent 50 years and it presented seasonal variation during the whole year.Precipitation in spring and autumn exhibited significant decreasing trend; in contrast,there was not an obvious upward trend for precipitation in summer and winter.There was an obvious periodic oscillation in annual precipitation,and 22 years was the first primary period.Abrupt change points of annual precipitation was at 1984,1991 and 2001,respectively.There were different abrupt changes and periods in seasonal precipitation.Changing in precipitation of different time scales increase the probability of extreme precipitation event and intensify the risk of agricultural drought disaster.
precipitationspatial and temporal characteristicsPCIMann-kendall testMorlet wavelet analysisGuizhou Province