Abstract: Based on the precipitation data of 103 meteorological stations and the water resource data of 18 provincial cities in Henan Province, the spatial distribution and change characteristics of precipitation and water resources in the whole province in 1956-2007 were analyzed, and the wet/dry years of precipitation and water resources were also assessed. The water resources were estimated from the precipitation data by using the linear correlation method and the water-producing coefficient method, respectively; and their precisions were compared and analyzed. The results indicate that: 1) the annual precipitation resource for the whole province showed an overally slowly decreasing trend with the rate of 2.32×108 m3/10a in recent 50 years; however, the precipitation resource is not spatially uniform, and it exhibited decreasing trends in north, west and central Henan Province, but increasing trends in the rest sub-regions of the province. 2) The total water resource for the whole province showed a decreasing trend with the rate of 10.85×108 m3/10a, which is larger than the decreasing rate of precipitation; it showed a slight decreasing trend in all sub-regions of the province, the reduction is the most obvious in west Henan, next in north Henan, and least in central Henan. The decadal change characteristics of water resource are basically similar to those of precipitation resource. 3) There appears a good relationship between total water resource and annual precipitation, and the mean error of the annual total water resource estimated from annual precipitation is about 10%-22%. The estimation error might be diminished if the water-producing coefficient method is used to anomalous high/low water flow years, the linear correlation method for other years, respectively.

Key words: Henan Province, precipitation, water resources, estimation, evaluation