Spatial Interpolation Of Precipitation In Hanjiang Basin

Precipitation is the main entry of hydrological model, whose spatial distribution is themain factor of affecting runoff simulation. Hanjiang River is the largest tributary in theYangtze Basin. There is abundant precipitation, mainly in the summer. The terrain iscomplex and rugged in Hanjiang Basin, so it accelerates the process of collectingrainwater. Because of the amount of serious imbalance between river channel dischargecapacity and flood flow, floods occur frequently.This paper bases on the average daily precipitation data of19meteorological stationsof Hanjiang Basin on August2005, uses the ARCGIS10.0platform, and uses fourinterpolation methods that is the global polynomial interpolation, inverse distanceweighted interpolation, ordinary kriging and co-kriging. I get spatially continuousdistribution of precipitation information in Hanjiang Basin. By comparing, the result ofanalysis is:(1) The average daily rainfall on August2005in space shows obvious gradientthat rainfall increases gradually from west to east. During the process of co-kriginginterpolation, I select the appropriate the number of fitting function, semivariogram model,semivariogram directional angle and step size, altitude. The accurate of result consideringaltitude and precipitable is higher than only considering altitude and only consideringprecipitable. By Comparing with the output of four kinds of interpolation methods, itshows that the accuracy of co-kriging interpolation is better than the other threeinterpolation methods.(2) using different number of meteorological stations, time scalesand interpolation methods, I analyze the uncertainty of the Precipitation Interpolation inHanjiang Basin. The result shows that, the more the number of meteorological stations, theaccurate is higher; the greater the timescales, the uncertainty is smaller; using differentinterpolation methods, the results will be very different.