近50年黄河流域气温和降水量变化特征分析

Variation of Precipitation and Temperature in Yellow River Basin during the Last 50 Years

利用黄河流域54个气象站点1961-2010年气象数据,探讨近50a黄河流域气温和降水量的变化趋势特征。结果表明:(1)黄河流域年降水量变化具有明显的空间差异,总体表现为上游地区增多、中游地区减少的特点。春季上游降水量呈显著增加趋势,秋季中游显著减少,冬季全流域降水量均呈显著增加趋势,其中下游增幅最大。年内降水量显著增加的时段主要集中在1-3月和12月;(2)黄河流域气温变化呈显著升高趋势,平均最高气温和最低气温变化具有明显的不对称性,平均最低气温变化对平均气温升高的贡献率大于平均最高气温。平均最高气温、平均气温和平均最低气温全流域均表现为冬季增幅最大,夏季和秋季则为流域上游增幅最大。月平均气温显著增加的站点比例最高,月最高气温显著增加的站点比例最小,且均集中在2月。(3)全流域冬季出现暖湿化趋势,春季上游出现暖湿化趋势,而秋季中游出现暖干化趋势。

The variation of temperature and precipitation in the Yellow River Basin was analyzed based on meteorological data at 54 metrological stations during 1961 -2010. The results showed that the annual precipitation increased in upper and decreased in middle of the Yellow River Basin. The precipitation increased in upper in spring, decreased in midlist in autumn, and increased during whole winter, especially from January to March, and December. Temperature increased, but maximum and minimum temperature changed non-symmetrically. Annual maximum, mean and minimum temperature increased with an amplitude peak in winter in whole basin, which increased obviously in summer and autumn. The increase rate of monthly mean temperature was highest, followed by monthly minimum temperature. It tended to warming-wetting during winter in whole basin and same in upper during spring, warming-drying in autumn in middle stream.