Ensemble Of Precipitation And Analysis Of Relationship Between Precipitation And Humidity By Muti-models

In order to simulate rainfall better, this paper proposes a method of weighting the standardized time series. Monthly precipitation data from the IPCC-AR410 models for 20C3M and A1B emission scenario and IPCC-AR5 10 models for Historical and RCP4.5 emission scenario are used in this study. Result show that the root mean square error(RMSE) of Normalized ensemble(NES) is significantly less than the models, the simple multi-model ensemble method(SMMEM) and Taylor weighted ensemble (Taylor). That is, the ensemble simulation of the Normalized ensemble is better than both SMMEM and Taylor; Through re-prediction, we can found that more reliable prediction of future climate of precipitation can be approached. In the RCP4.5 scenario for the period 2013-2099, rainfall over china generally increased and the trend has obvious regional differences. The rainfall over the middle and lower reaches of the Yangtze river region, northeast China, southwest China and south China will increase significantly, and rainfall over the southern will decrease weakened. In order to deepen understanding of the change in the future rainfall, we explore the trend of precipitation(Pr) and relative humidity(RH) and its relationship so as to obtain new discoveries. We have analyzed the long-term trends of the mean JJA RH at various levels and Pr for the period 2006-2099 with the global precipitation and relative humidity data which provided by the RCP4.5 scenario of the IPCC-AR5. Evidence show that the global average Pr of 18 climate models will increase and global average RH at difference levels will decrease except FGOALS-g2 model. In addition, there is a good correlation between the trends of Pr and RH at 400hPa to 850hPa. As a result, it is concluded that when the RH increases, Pr will also increases; when the RH reduce weakened, there still allow increased Pr. Form the truth that global average of the number of downfall day of JJA will raise, we can guess that increase in Pr may be due to increased of heavy precipitation.