中文摘要：

以淮河流域为研究对象，结合淮河流域35个气象站点1961—2013年的逐日降水量观测数据与流域地表气象数据，运用Penman—Monteith公式计算得到淮河流域的潜在蒸散量及相对湿度指数，并用Matlab软件的小波函数进行周期分析及Mann—Kendall趋势分析，研究近53年来淮河流域地表干湿变化的时间变化特征。同时借助ArcGIS平台，通过反距离权重法插值，研究淮河流域的降水量、潜在蒸散量和相对湿度指数的空间分布特征。结果表明，在时间分布上，近53年来淮河流域的降水量和相对湿度指数均呈现微弱上升趋势，而潜在蒸散量呈下降趋势；在空间分布上，潜在蒸散量表现为淮河地区北部高于南部，而相对湿度指数和降水量则均表现为淮河地区南部高于北部。

英文摘要：

Terrestrial water cycling encompasses mainly three factors, including precipitation, evapotranspiration and runoff, and dry or wet of the climate mainly depends on precipitation and evapotranspiration. Crop evapotranspiration is a major index to take into account in assessing climate drought degree, crop potential productivity, vegetation water consumption, and water resources supply and demand balance. And it may also provide a scientific basis for calculating crop water requirement, evaluating agricultural water resources, and developing reasonable irrigation schemes. It is generally believed that rising temperature will speed up surface evapotranspiration, and aggravate surface drought degree, while precipit ation will increase will supplement the soil with water and relieve the surface droughtiness to a certain extent. So research and analysis on precipitation and evapotranspiration is of certain reference value to evaluating surface soil moisture conditions. The Huaihe River Basin, located between the Yangtze River basin and the Yellow River basin in the east part of China, is a transitional zone between the north and south climates in this country, and belongs to the warm temperate semi-humid monsoon climatic region. Because of its special geographical position, the complexity and variability of its climate and frequent subjection to the impacts of convergence of cold and warm fronts from the north and south, precipitation varies freq uenly and sharply, thus often leading to occurrence of droughts or flooding in this region. In the context of global warming, whether the climate in this region will change as affected by the factors mentioned above, how it will change, and what the development trend will be, are problems that call for systematic research. So analysis of changes in surface soil moisture content of the region will be of some practical significance. The precipitation data of the region monitored day by day were calculated and analyzed, and potential evapotranspiration and relative humidity at ea