1961—2010年黄河流域蒸发皿蒸发量变化及影响因子分析

利用黄河流域内61个气象站逐月观测资料，使用Mann-Kendall非参数检验方法对1961—2010年黄河流域小型蒸发皿蒸发量变化趋势进行了分析，并用SVD和多元回归方法检测影响蒸发量变化的因子。结果表明，黄河流域年蒸发皿蒸发量在1961—2010年显著下降，四季中夏季的下降趋势最显著，年和春、夏季蒸发量均在1979年发生突变。上、中、下游的年蒸发量变化率分别为-2.38 mm/a、-2.35 mm/a、-8.35 mm/a，下游下降幅度较大。空间变化分布上，年和春、夏季蒸发皿蒸发量均在黄河流域河源地区、河套地区西部及北部、河南北部有显著下降趋势，在河套地区东部呈显著上升趋势。利用SVD分析发现蒸发量的空间变化与不同因子作用有着显著关联，通过对不同区域内各影响因子的多元回归分析发现流域内蒸发量上升的地区主要是由气温上升所引起，而下降的地区则与风速减小有关。

Analysis of Pan Evaporation Change and the Influence Factors in the Yellow River Basin in 1961-2010

Based on monthly observational data sets of 61 meteorological stations from 1961 to 2010, the pan evaporation trend and abrupt change in the Yellow River basin were analyzed by using Mann-Kendall test method, and then the influence factors were detected and analyzed by using multiple regression method and SVD (Singular Value Decomposition). The results show a significant decreasing trend in annual evaporation in 1961-2010, and the most significant decreasing trend occurs in summer. The abrupt changes of annual, spring and summer evaporation occurred in 1979. In the upper, middle and lower reaches of the Yellow River, the annual evaporation decreased at the rates of 2.38 mm/a, 2.35 mm/a and 8.35 mm/a, respectively with the most significant decreasing trend in the lower reaches. As to the spatial distribution, annual, spring and summer evaporation decreased significantly in the river source region, the west and north parts of Hetao region and the north part of Henan Province, while increased significantly in the east part of Hetao region. By using the method of SVD, it is found that there is a correlation between the spatial change of evaporation and different factors. Based on the multiple regression results, it is concluded that in the region with increasing evaporation, the main influence factor is temperature, whereas in the region with decreasing evaporation, the main influence factor is wind speed.