An application of the generalized linear statitical downscaling method to simulating daily precipitation

An applicational study of the statistical downscaling method of Ucneralized Linear Model (GLM) was carried out on downscaling daily precipitations. Applying the observational daily precipitation data and the NCEP rcanalysis data from 1960 to 2010,the study focuses on two regions-the Tibetan Plateau and the lower valley of the Yangtze River. The GLM method shows good ability in simulating daily precipitation during the simulation period (1960-2005): the correlation coefficients for the two regions between the simulations and the observations are around 0. 75 in January and above 0. 5 in July, and the simulations are generally greater than the observations with small biases,while the accuracy of simulating no precipitation is much higher with the biggest value being 85. 2% for the "hibetan Plateau in January. Meanwhile,the simulative daily precipitation during the test period is good consistent with that during the simulative period. In addition,a further analysis shows that the GLM has good ability in simulating heavy precipitation as well as no precipitation. And,the GLM retrieves the main rainfall processes successfully, In short,the good performance of the GLM method in downscaling daily precipitation makes it suitable for applying to relevant climatological researches.