Comparison and Analysis of Different Variogram Functions Models in Kriging Interpolation of Daily Rainfall

Ordinary Kriging is a wide-used method of geostatistical interpolation. However, it is only one variogram function that is often used to calculate the estimated value depending on one’s experience. Meanwhile, there is lesser study about daily rainfall comparison of different variogram functions in ordinary Kriging because most of the recent researches emphasize yearly and monthly rainfall. To obtain the better fitted variogram function in ordinary Kriging for daily rainfall interpolation within four different variogram functions (exponential, spherical, gauss, linear). The study leans on 16-year (1990-2005) daily rainfall data at 43 raingages in and around Mishui Basin. According to the comparison of three aspects including the correlation coefficients, examine index, accuracy of different precipitation grade, the result of crossvalidation shows that: 1) exponential and spherical functions can fit the daily rainfall interpolation better in ordinary Kriging; 2) the estimated value in ordinary Kriging is generally smaller than observed value on days of heavy rainfall; 3) the error of daily rainfall interpolation increases with the precipitation grade.