黄河源区地表湿润指数及与气象因素的敏感性分析

Soil Surface Humidity Index and Sensitivity Analysis of the Climate Factors That Affect It in the Yellow River Source Regions

应用Penman-Monteith模型计算了黄河源区地表潜在蒸散,分析了区域1961-2009年49 a来地表湿润指数的变化特征和趋势,并进行影响地表湿润指数的气象因素敏感性分析.结果表明:49 a来黄河源区年地表湿润指数呈减小趋势,其中20世纪60年代相对湿冷,70年代半湿冷,80年代为弱暖湿型,90年代暖干化明显.但进入21世纪初,特别是2003年以来,黄河源区降水增多,湿润指数上升,表现为暖湿型的气候特征.不同季节湿润指数变化略有不同,比较而言,49 a来地表湿润指数在冬春季呈增加趋势,夏秋季呈减小.湿润指数对降水量、日照时数和相对湿度的响应最为敏感.

The potential evapotranspiration in Yellow River source regions was calculated by using the model of Penman-Monteith.The variations and changing tendency of the regional surface humidity index since 1961 were analyzed,together with a sensitivity analysis of the meteorological factors that affect the index.It is found that surface humidity index has had a decreasing tendency since 1961,with a relative wet and cold period in the 1960s,a semi-wet and cold period in the 1970s,a minor warm and humid period in the 1980s and a major warm and dry in the 1990s.However,precipitation has increased and humidity index has enhanced since the beginning of this century,especially since 2003,which characterized by warm and wet.There is a little difference in the humidity index among different seasons.The surface humidity index has increased in spring and winter while decreased in summer and autumn during the past 49-year.The analysis shows that precipitation,sunshine-hour and humidity are the most principal sensitive factors to the humid index.