Analysis on the Spatio-temporal Variability of Rainy Season Precipitation in Henan Province

With the extensive application of geographic information systems and the deeply development of geography disciplines,the spatial and temporal structure and process analysis are receiving more attention.The analysis of spatio-temporal variability of precipitation is the basis for the understanding of formation and development of regional water resources.It not only reveals the change of time-series,but finds the spatial structure and changing pattern.Thus,it provides the basis for predicting the drought and waterlogging.Based on the rainy season precipitation data of the past 51 years in Henan Province,combined with a digital elevation model(DEM),using regression analysis,spatial autocorrelation,simulation of spatial interpolation,and cross-validation,we conducted an analysis of spatial and temporal variability of precipitation in Henan Province.The result reveals that:(1) the trend is clear,and the rainy season precipitation in Henan Province overall has shown an increasing trend and in recent years it is particularly evident;(2) The differences of monthly precipitation are obvious,the maximum value is in July,and the average reaches 178.3 mm.(3) The spatial variance exists.There is a clear pattern that the precipitation in the south and east are more than that of north and west in spatial.There is a strong clustering characteristic that in the south,Luoshan and Huangchuan counties as the center formed the rainfall abundant areas,while in the north,Hui County as the center formed the rainfall scarce areas.Lin,Luanchuan and Xixia counties as spatial outliers,are significantly higher than the adjacent regional precipitation.After the spatial autocorrelation analysis,the spatial and temporal anisotropy can be acquired.Therefore,according to the spatio-temporal analysis,we get the interpolation map with Cokriging method,and it tallies with the prior conclusion.