| Based on the 84 daily precipitation and temperature from meteorological stations during 1961-1979 and 996 daily precipitation and temperature from 0.5°×0.5°gridded datasets during 1961-2014 in the Tibetan Plateau(TP)released by the National Meteorological Information Center,and analyzed the meteorological stations datasets and obtained the critical temperature of each stations.The critical temperature is applied to other regions where there are no meteorological stations by ArcGIS,and then obtained critical temperature of each grid for 996.In this paper,based on the critical temperature,the gridded precipitation was divided into the rainfall and snowfall and analyzed the snowfall/precipitation ratio(S/P)in the Tibetan Plateau during 1961-2014.The main conclusions as follows:(1)Although the mathematical statistical method cannot separate the sleet from the precipitation,its better simulation for rainfall and snowfall was better.So this method was applied to divide the precipitation to rainfall and snowfall,and which have certain reliability.(2)From the annual variation,the rainfall shows an increasing trend that is relative weak in the winter.Meanwhile,the snowfall shows a decreasing trend,but is increasing in the spring and winter.(3)From the spatial variation,the rainfall shows an increasing trend and the snowfall shows a decreasing trend.The spatial distribution of seasonal rainfall and snowfall shows a different characteristic in the TP.The rainfall shows an increasing trend in summer and autumn,but shows a decreasing trend in spring and winter.The snowfall shows an increasing trend in spring and summer,but shows a decreasing trend in winter.(4)The temperature shows an increasing trend in the TP during 1961-2014.The warming trend is more obvious in the central of the TP,and more area is statistically significant at the 0.01 level.In the southeast of TP,the warming is lower than the center in the TP.So the temperature shows a rise hugely trends in the center than the edge of the TP and the north is higher than the south of the TP.(5)The inter-annual and seasonal changes of S/P show decreasing trends in the TP,and are statistically significant at the 0.01 level.The spatial distribution ofinter-annual and seasonal of S/P show greatly changes,and mainly show decreasing trends.(6)The temperature,rainfall and snowfall have different effects on the S/P changes.The warming is one of importation reasons to leading the decreased of S/P,and the increased rainfall and decreased snowfall have a positive effect on the decreased S/P.At the same time,with the change of the elevation the S/P shows a decreased trend in the elevation of 3000 m-5000 m.In addition,the climate indexes have different effects on the changes of S/P. |
