45a来塔里木河流域气温、降水变化及其对积雪面积的影响

Climate Change and Its Impact on Snow Cover Area in the Tarim River Basin over the Last 45 Years

对塔里木河流域19个台站45a（1958—2002年）的气温、降水序列进行非参数检验，查明其变化趋势及特征，在此基础上，对近20a（1982—2001年）流域的积雪面积（SCA，％）变化进行趋势与相关分析．结果表明：流域的气温和降水均在20世纪80年代中期发生了阶段式的跳跃增长，气温和降水增加的主要季节分别为冬季和夏季．流域总体的积雪面积呈缓慢增加态势，其中北区和西区增加较为稳定，而南区相对不稳定．在垂直方向上，海拔〈2500m的区域积雪面积表现缓慢增加，而海拔≥2500m的区域则减少．相比较，低海拔区域更易受降水影响，而高海拔区域更易受气温影响．海拔2500～5000m的高度带是对气候变化较为敏感的区域．20世纪90年代与80年代相比，降雪和融雪的速度都更快．积雪与冷季降水呈正相关，但与冷季气温没有明显的相关关系．

In this paper, the series of annual mean temperature and precipitation at 19 observation stations during 1958--2002 were investigated by non-parametric test in order to find their trends and features of climate change. Based on the investigation, the trend and correlation analyses of snow cover area from 1982 to 2001 were further made in this paper to reveal the effect of climate change on snow. The results showed that both temperature and precipitation had a jump in the mid 1980s. Temperature and precipitation significantly increased in winter and summer, respectively. The SCA of the entire basin showed a slow increasing trend, with a stable increasing in the northern part and the western part and a relatively unstable increasing in the southern part. In the vertical direction, the SCA in the zone below 2 500 m a. s. 1 increased slowly, and that in the zone above 2 500 m a. s. 1 decreased. It was easy to be control by precipitation in the zone at low altitude, and to be control by temperature in the zone at high altitude. The zone from 2500 m to 5000 m was most sensitive to climate change. The speeds of snowfall and snowmelt were higher in the 1990s than that in the 1980s. The SCA had positive correlation with precipitation in cold season, but no pronounced correlation with temperature in cold season.