黄河流域近40年日照百分率的气候变化特征

Variation of Sunshine Percentage for the Last 40 Years in the Yellow River Basin

利用黄河流域及其周边146个气象站1960—2000年逐月日照百分率资料,研究分析了黄河流域日照百分率的气候变化趋势。结果表明,就整个流域平均而言,日照百分率呈明显下降趋势,黄河流域年平均日照百分率在20世纪90年代较60年代下降了2.49%;日照百分率的下降主要表现在夏季和冬季,春季和秋季下降不明显。对日照百分率气候变化的空间分析表明,除极少数台站的日照百分率呈略有上升趋势外(主要出现在流域上游),黄河流域日照百分率的下降表现得非常明显,遍布整个流域的中、下游。

Based on observational data of 146 meteorological stations around the Yellow River basin from 1960 to 2000, the spatial and temporal distributions of the sunshine percentage are studied. The result shows that the sunshine percentage in the Yellow River basin has steadily decreased on average, especially in summer and winter. Compared with the 1960s, the sunshine percentage of 1990s decreased in the middle and lower reaches of the Yellow River, and increased a little in the upper reach.