黑河山区气温与降水的季节变化特征及其区域差异

The Seasonal Change Characteristics of Temperature,Precipitation in the Mountain Areas of the Heihe River and Their Regional Differences

基于黑河干流上游山区(以下简称黑河山区)及周边有关台站的观测数据,对该区域1960—2013年气温、降水的季节变化特征及区域差异进行分析。结果表明:黑河山区干、支流各区的气温变化与全球气温变化有着较好的一致性,气温升幅率明显高于过去50 a全球与中国平均气温的升幅,年平均气温的年代际变化的上升趋势比年际变化的更为显著,但不同区域年与各季气温的上升幅度存在着一定的差异,各区气温的气候倾向率变化呈现出一种由南向北逐步减小的趋势。其中,位于中高山地区的东、西支流域冬季气温升幅最大,位于中低山区的干流区则以秋季气温升幅最大,且各区均以春季气温升幅最小。东、西支流各区年平均与各季节气温发生变暖的突变时间基本上出现在1990年代中后期;干流区年平均与各季节气温发生变暖的突变时间差异较大。尽管山区干、支流各区各季节降水均呈波动增长的态势,但年降水量增幅差异较大。其中,以东支增幅最大,干流区增幅最小;各区各季降水量的年际变化总体上亦呈波动增长的态势;夏秋季降水增加比较明显,冬、春季降水量变化趋势不明显。各区年与各季降水量的年代际的变化较年际变化波动更为剧烈。冬春季降水波动幅度大于夏、秋季降水;各区各年代降水量增加或减少并不完全同步。东、西支两区年降水量系列均在1974年发生降水量增加的突变,而干流区年降水则无明显的突变点;东、西支两区春、夏、秋三季降水量系列均有明显增加或减少的突变点,但出现时间不一致;干流区除夏季降水在1970年初发生明显增加的突变外,其他各季降水量均无明显突变点;除西支冬季降水量在1970年中期后发生明显增加的突变外,整个山区冬季降水量均无明显突变点。总体上讲,黑河山区气候持续转向暖湿,受其影响,黑河出山径流目前的丰水态势仍将会持续下去。

Abstract：Based on the observation data at the involved stations, the seasonal variation characteristics of the temperature and precipitation in the mountain area of main stream of Heihe River （ hereinafter referred to as the mountain area of the Heihe River, Gansu of China） during the period from 1960 to 2013 and their regional difference were analyzed. The result shows that all annual and seasonal temperature changing processes in the mountain area of the Heihe River and its every sub-region have being presented the rising trend, which is consistent with the global temperature changing trend, and the rise rates of annual mean temperature in the area is significantly higher than the rise rates of global and China＇s mean temperature. The rising trends of the interdecadal mean temperature are more significant than that of the annual mean temperature in the area in the past over 50 years. But, there were some difference in the rise rates of the annual and seasonal average temperature and the climate tendency rates decrease gradually from the south to the north in the each sub-region of the mountain area of the Heihe River. Thereinto, the rise rates of winter temperature were largest in the east and west branch sub-region located in higher alti- tude, and the rise rates of autumn temperature were largest in the main stream sub-region located in lower altitude. The rise rates of spring temperature were smallest in every sub-region. All abrupt changes of annual and seasonal average temperatures in the east and west branch sub-region occurred in the mid and late 1990 s. There were larger difference for the time points of abrupt change of annual and seasonal average temperatures in the main stream region. Precipitation change is more complex than air temperature in the each sub-region of the mountain area of Heihe River. Overall, all changes of precipitation in every sub-region in the mountain area presented an increasing trend, and had some difference in the increasing extent in the annual precipitation in each sub-region. Thereinto, the increased extent of annual precipitation in the east branch sub-region were largest, and that in the main stream region was smallest. Although yearly changes of precipitations the mountain area of Heihe River presented an in- creasing trend as a whole, the rate of increase of the precipitation in each sub-region in each season has large differences. Thereinto, the increasing in summer and autumn were quite significant, and that of precipitation in spring were significant tend for the changes and winter in every sub-region. Fluctuate of inter-decadal variations of the precipitation in each sub-region in each season were more violent than their yearly variation, and the fluctuation range of precipitation in winter and spring were larger than that in summer and autumn. The increase or decrease of precipitation was not synchronized in each subregion of mountain area of the Heihe River. All abrupt changes of annual precipitation series in the east and west branch sub-regions occurred in 1974, and there are not obvious abrupt changes in annual precipitation series in the main stream region. There were obvious abrupt change points for all the precipitation series in spring, summer and autumn in the east and west branch regions, but abrupt change appearing times were inconsistent. Except abrupt change of summer precipitation occurring in the early 1970 s, all precipitation in other each season had no obvious abrupt change point in the main stream region. Except the abrupt change of winter precipitation series in west branch regions occurring in the mid 1970 s, all precipitation series in other each sub-region had no obvious abrupt change. In a word, the climate in mountain area of the Heihe River turned sustainedly to warmth and moist. Affected by the warm and wet climate, the current high flow conditions of the mountain runoff of the Heihe River which is supplied mainly mountain precipitation and ice, permafrost and snow melting water by will still continue.