淮河流域冬春季土壤温湿度异常对夏季降水的影响及其应用的研究

夏季降水异常与前期环流、下垫面异常有密切的关系 ,文中重点研究了淮河流域前期下垫土壤温、湿度异常对夏季降水的影响。提出了一种动力与统计相结合寻找影响降水的因子的方法 ,通过将大气中的热量、水汽收支方程与一个简化的两层土壤温度、湿度方程相结合 ,并依据月尺度大气环流的演变特征 ,推导出月降水距平与 5 0 0hPa月平均高度距平场、土壤深浅两层温、湿度的关系 ;并利用台站观测资料 ,使用统计反演方法确定方程中各项的系数和量级 ,从而找出影响降水的主要土壤温、湿度因子 ;利用统计方法建立这些因子与淮河流域夏季降水异常之间的简单线性预报方程 ,并对 1982～ 2 0 0 0年淮河流域夏季降水趋势进行回报 ,结果表明 :对淮河流域夏季降水趋势的预测有很好的效果 ,且更加明确了土壤温、湿度因子与降水异常之间的动力学联系。

IMPACT OF HUAIHE RIVER BASIN SOIL TEMPERATURE AND HUMIDITY ABNORMALITY IN PRE-WINTER AND SPRINGTIME ON THE ANOMALOUS SUMMER RAINFALL AND ITS APPLICATION

Since the summer rainfall abnormality has close relationship with both the soil moisture and temperature abnormality. We study the impact of pre wintertime and springtime soil moisture and temperature on the summer rainfall over Huaihe river basin. In this paper, we present a blending method of dynamical and statistical approach to choose the attributing factors that may effect the precipitation. The approach has established a relationship between monthly precipitation abnormality and monthly circulation, soil moisture and temperature on the shallow and deep layers. The relationship is the precipitation diagnostic equation and its coefficients and dimensions are determined by using the observed data of Huaihe river basin. Then we select the mainly soil moisture and temperature attributing factors by the dimensional analysis to establish a forecasting equation of summer precipitation over Huaihe river basin with the statistic approach. The results indicate that those soil factors, which are selected by the blending method of dynamical and statistical approaches, are useful for forecasting monthly summer precipitation and can expressly discover their dynamical relationships.