石羊河流域1951-2005年气候变化特征

Characteristics of climate change in Shiyang River Basin from 1951 to 2005

运用区域空间和时间的平均视角,采用气候倾向率、距平、累积距平、5a滑动平均等指标,对石羊河流域1951-2005年气候变化过程进行了研究,初步探讨了气象要素的变化特征及规律。结果表明,过去50a,全流域及上、中、下游,降水量分别表现为减少、减少、增加、增加状态,上游以1962年为转折点明显减少,中、下游从90年代起出现明显增加;气温变暖趋势明显,其中下游增加程度最高,中游次之,上游最低,上、中、下游分别以1987、1997和1987年为转折点出现明显增加,尤其是2000年以来增幅较大;全流域及上、中、下游,风速呈下降、增加、下降、下降状态,上游在90年代增幅明显,80年代至今逐渐趋于平稳,中游以10年为周期波动变化,下游以1984年为拐点明显下降,2000-2005年为最低阶段;湿度呈下降趋势,50年代中期至60年代中期下降较为明显,中游在90年代末出现大幅度降低,1999-2005年为最低时期;目前中、下游干旱程度有所缓解,今后一段时间内,全流域干旱程度将逐渐改善。

Based on meteorological data in Shiyang River Basin from 1951 to 2005, the present study ana lyzed the characteristics of the climate changes in this area. In the past 50 years, precipitation in the whole river basin and the lower reach decreased, but the upper and middle reaches increased. Precipitation in the upstream significantly decreased since 1962 as a turning point, and in the middle and downstream signifi cantly increased from 1990s. There was an obvious increasing trend in atmospheric temperature which was more obvious in midstream followed by midstream and was less obvious in upstream. For the upper, mid dle, and lower reaches, there was significant increase since 1987, 1997 and 1987, respectively, and there was significant increase especially since 2000. Wind speed of Shiyang River Basin decreased, increased, decreased, and decreased at different stages. The wind speed in the upstream significant increased in 1970＇ s and gradually stabilized since 1980＇s. The wind speed in the midstream changed with 10 a cycle. The wind speed in the downstream increased first and decreased since 1984 as a turning point. The lowest stage appeared during 2000--2005. Humidity in Shiyang River Basin decreased which more obvious from middle 1950＇s to middle of 1960＇s. However, there was significant humidity reduction in the midstream in therelieved which suggested the situation in the whole basin will be gradually improved.