Abstract:

Based on the daily precipitation data from 90 weather stations in the northeast China during 1961-2010, the climatic characteristics of precipitation events and its temporal and spatial homogeneity were analyzed. The results indicate that the annual precipitation is in a slightly decreasing trend, while winter and spring precipitation increases significantly. The increase of precipitation in spring and winter is mainly associated with the increase of precipitation intensity, while the decrease of precipitation in summer and autumn is with the decrease of precipitation frequency in terms of the number of precipitating days. Although a linear trend of annual precipitation is not significant, the inhomogeneity of the inter-annual precipitation increases. There is a trend that precipitation tendency is moving towards extreme direction, especially in summer and autumn. The inter-annual precipitation events in various grades are inhomogeneous, especially for snowfall events in the last 20 years. The spatial homogeneity of annual precipitation shows an abrupt change in 1993, while that of annual precipitation days is in 1986.After the abrupt change, the spatial inhomogeneity of the former increases and homogeneity of the latter fluctuates significantly. The variation of precipitation events is likely to increase the risks of flood and drought in the northeast China, so is the events that flood in some regions and drought in other regions occur simultaneously.

Key words: Northeast China, Precipitation event, Spatial and temporal homogeneity