Spatio-temporal Variations of Temperature and Precipitation in Mts. Hengduan Region during 1960-2008

Based on daily temperature and precipitation data of 27 stations in the Mts. Hengduan region, methods of spline interpolation, regression analysis, least square, moving average were employed to analyze the climatic changing trend and spatial differences under the background of global warming. Results indicated that temperature patterns are consistent with warming at statistical significance level during 1960-2008, and relatively low in the 1960s and 1980s, whereas it started to rise after the 1980s which can be proved by a 0.46 oC temperature increase in 2000-2008. The average temperature of all the year, spring, summer, autumn and winter exhibited an obvious increasing trend roughly centered in the area of Mt. Meili and the southernmost between Mt. Shaluli and Mt. Daxue with the velocity of 0.15 oC 10a-1, 0.589 oC 10a-1, 0.153 oC 10a-1, 0.167 oC 10a-1 and 0.347 oC 10a-1, respectively. And what's more, temperature increase is more obvious from lower to higher altitude. Precipitation is relatively more after the 1980s, which can be confirmed by a 29.84 mm increase in the 1990s, but it started to decrease after 2000. The average precipitation of all the year, spring, summer, autumn and winter changed by 9.09 mm 10a-1, 8.62 mm 10a-1,-1.5 mm 10a-1, 1.53 mm 10a-1 and 1.47 mm 10a-1, respectively, roughly centered in the area of Mt. Meili and the southernmost between Mt. Shaluli and Mt. Daxue, and only the spring is significant at the 0.05 level. Under the influence of the longitudinal range-gorge, the regional trend in precipitation was on the decrease from southwest to northeast and from south to north in the Mts. Hengduan region. In summer monsoon, the regional trends of temperature and precipitation are 0.117 oC 10a-1 and 6.01 mm 10a-1, respectively, but the precipitation also started to decrease after 2000. There is also a 0.25 oC 10a-1 and 7.47 mm 10a-1 increase of temperature and precipitation in winter monsoon.