An Analysis Of The Diurnal Temperature Range In China And Its Association With The Diurnal Variation Of Precipitation

This paper based on the daily air temperature, China’s diurnal temperature range of time and space distribution characteristics were analyzed and its long-term trends were discussed. China’s spatial distribution characteristics of daily variation of precipitation were also analyzed based on the ground based station precipitation data sets from the September to June provided by national meteorological information center. Interannual variability of diurnal variation of precipitation was further obtained. Finally, numerical analysis for the relationship between diurnal temperature range with diurnal variation of precipitation was accessed by LMDZ regional climate model and WRF so as to reveal the regional response of the diurnal variation of precipitation to the decrease of diurnal temperature range. The main conclusions are as follows:(1) The spatial distribution of average diurnal temperature range is bounded by Qinling mountain and Huaihe river, and the northern’s is bigger, smaller in the south. The trend for the DTR in 1961-2010 is negative, especially in northeastern and northwestern, while the DTR in Hetao was positive. The EOF model and mode2 showed the decline trend and the average spatial distribution respectively. The patent revealed by the two EOF model is always last for the process of DTR revolution.(2) The spatial distribution for the regional hour average rainfall, hours average rainfall frequency and average rainfall intensity present decreasing trend from northwest to sourtheast. In eastern Sichuan basin and the Qinghai-Tibet plateau region, south China coastal areas and the Yangtze river basin, the characteristics of daily variation of precipitation in these areas is very significant. Hour average rainfall have significant negative correlation relationship with diurnal temperature range.(3) WRF model’s simulation results can generally reflect the spatial distribution characteristics of diurnal temperature range. And the value of model’s results are smaller than observations. Using the method of increasing the albedo can realize the decrease of DTR. The phase of the daily cycle of the precipitation changes most is in Sichuan Basin. With the smaller of DTR, the rain that happens in night become less. (4) The simulation value of the LMDZ model was lower than that of the observations. But in terms of spatial distribution, the simulation results of the model are basically identical with the observation. In general, in the scenario of historical, the LMDZ model’s results for theDTR is not very well. The simulation value for the hour average rainfall is bigger than observation, while the spatial distribution form is consistent with the observation.In the scenario of RCP4.5, diurnal temperatue range decreased greatly in the western area of northeast, but southeast coastal region of diurnal temperature range increased significantly.