长江上游气温、降水和干旱的变化趋势研究

基于长江上游1962~2012年的85个气象观测站的实测数据,统计分析了该区域气温和降水的变化趋势,并结合SPEI(standardized precipitation evapotranspiration index)指数评价分析了干旱的变化趋势。研究结果表明:长江上游年平均气温呈现上升的趋势,增温率为0.195℃/10a,秋、冬平均气温呈现明显的上升趋势;多年平均气温最高的地区集中在长江上游的南部和东部,西北部最低;多年平均年降水量变化趋势不显著,降水季节性变化差异比较大,春季和冬季的降水量呈现上升的趋势;多年平均年降水主要集中在东部地区,西北部最低。SPEI指数的分析结果显示,长江上游区域干旱状况整体呈现加剧的趋势,干旱次数和干旱程度均加剧,长江上游东部地区干旱趋势最为严重,西北部地区呈现变湿趋势。

Variation trend analysis of temperature,precipitation and drought in upper Yangtze River Basin

Based on the observed data of 85 meteorological stations in the upper Yangtze River Basin from 1962 to 2012, the variation trends of temperature and precipitation in the region were statistically analyzed. Meanwhile, the variation trend of drought was analyzed by SPEI (standardized precipitation evapotranspiration index). The results show that the annual average temperature increase at a rate of 0.195 ℃/ 10a in the upper Yangtze River Basin, especially in the autumn and winter; the highest annual average temperature concentrates in the southern and eastern parts of the upper Yangtze River Basin, while the lowest concentrates in the northwest of the basin. The annual precipitation variation trend is not significant, and the seasonal variation trend is obviously different, and the precipitation in spring and winter increase. The multi-year mean annual precipitation is mainly distributed in the eastern region, and the lowest is in the northwest region. The SPEI shows that the drought situation has an increasing trend in the upper Yangtze River Basin both in frequency and degree, and the drought trend in the eastern part of the upper Yangtze River Basin is the most serious while the northwest region is becoming wet.