Temporal and Spatial Variation Characteristics of Precipitation during Crop Growing Season in Northeast China
LI Xiu-fen et al (Heilongjiang Institute of Meteorological Sciences,Harbin,Heilongjiang 150030)
[Objective]The aim was to understand variation characteristics of water resources and provide theoretical guidance for the formulation of agricultural irrigation methods.[Method]Taking the precipitation during crop growing season(from April to September) of 177 weather stations from 1971 to 2008 in Northeast China(Heilongjiang,Jilin and Liaoning) as data,temporal change and spatial distribution characteristics of precipitation during crop growing season were analyzed by means of small grid interpolation and climatic trend rate.[Result]The precipitation during crop growing season had decreased by 8.6 mm/10a in Northeast China.There were a period of relatively rainless from 1971 to 1980,a period of relatively rainy from 1981 to 1990 and an obvious decreasing trend from 1991 to 2008.But the decreasing trend was inconsistent in spatial,that was,the precipitation slightly increased in relatively rainless areas and obviously decreased in relatively rainy areas.[Conclusion] The areas with obvious decreasing trend of precipitation during crop growing season are the main grain zones in Northeast China,so the problem of food production security should cause enough attention.