Spatio-Temporal Trends in Seasonal Precipitation in Northeastern China from 1961 to 2004
1961年～2004年东北地区四季降水的时空演变特征

Seasonal precipitation data interpolated using Anusplin software from 1961 to 2004 with data from 146 weather stations in northeastern China were transformed to annual grid data using a GIS platform. Data from 26 weather stations were reserved in order to test the accuracy of the interpolation. The mean relative error for the four seasons was 14.3%, 14.1%, 18.1% and 25.1%. Then, spatio-temporal characteristics of seasonal precipitation in northeast China over the same period were evaluated with spatial analysis and time series analysis. The results showed that for temporal trends, the regional average seasonal gross precipitation (RASGP) in spring indicated a slight increase over the study period, with a clear increase before the 1980s and decrease after then. In summer, the RASGP decreased, especially after 1985. There was a slight decrease of RASGP in autumn, especially evident in the 1990s but recovering after 2000. The RASGP exhibited traits of inter-decadal change, and a slight increasing trend in winter with large variation over the last decade. For spatial distribution of seasonal gross precipitation from 1961 to 2004, in spring, northern and part of eastern Heilongjiang province as well as eastern Jilin province were the main regions where trends of increased precipitation were significant, ranging from 3mm/10a to 9 mm/10a. Areas where precipitation obviously decreased, with a range from 3mm/10a to 7 mm/10a, were mainly located in parts of central Liaoning province. In summer, precipitation decreased in the great majority of northeastern china. Central Heilongjiang province and the Liaodong peninsula were the main areas where precipitation decreased markedly, ranging from 20mm/10a to 40mm/10a. Most areas located in parts of eastern Heilongjiang as well as central and southern Jilin province were regions where precipitation decreased markedly, from 6mm/10a to 10 mm/10a in autumn. Hiemal precipitation increased from 1mm/10a to 3 mm/10a in most of Heilongjiang province and Jilin province, while decreasing in southern and part of western Liaoning province, from 1mm/10a to 2 mm/10a.