云南纵向岭谷地区气候变化对河流径流量的影响

以云南纵向岭谷地区历年逐月径流量观测数据和云南的逐月雨量和气温场观测数据为基础,应用统计分析和小波变换的分析方法,研究了云南纵向岭谷作用下的年际气候变化及其对国际河流年径流量变化的影响。结论为：由于云南纵向岭谷区的特殊下垫面作用,云南月降水量场变化与云南国际河流月径流量变化的高相关区中心的纬度差异不显著,但经度差异却十分显著;澜沧江气候区的年降水量明显大于其东部的李仙江和元江气候区的年降水量,其年降水量的偏差则明显小于它们;元江气候区的年平均气温明显低于其西部的李仙江和澜沧江气候区的年平均气温,其年平均气温的偏差也明显小于它们;与云南纵向岭谷作用下的年降水量变化特征相对应,元江的年径流量偏差也明显大于其西部的李仙江和澜沧江的年径流量偏差;云南纵向岭谷对西南季风的阻隔作用较大,而对东北季风的阻隔作用相对较小;云南纵向岭谷作用下的年降水量变化主要表现在较小的时间尺度上,随着时间尺度的增大其作用变小;云南纵向岭谷对于年气温变化的作用比年降水量变化的作用要小;近几年来,各气候区的年降水量变化的主要特征是偏多趋势,受其影响,云南国际河流的年径流量变化也主要表现为偏大趋势;近十几年来,各气候区的年气温变化的主要特征是显著偏高。

Climate Change of the Longitudinal Range-Gorge in Yunnan and Its Influence on the River Flow

Based on the observed data of the flow in the longitudinal range-gorge region and the data of monthly precipitation and air temperature field in Yunnan, and using the statistics and wavelet transforms, the interannual climate change under the effect of the longitudinal range-gorge and its influence on the international river flows are investigated. The results show that the latitude variations of the high correlation centers between the monthly precipitation field and the international river flows are not significant due to the role of special underlying surface in the longitudinal range-gorge region, but the longitude variations are very significant. The annual precipitation of the Lancang climatic region is obviously greater than that of the eastern Lixian River and Yuan River regions, but the standard deviation of the annual precipitation is significantly smaller than them. The annual mean air temperature of the Yuan River region is lower than that of the western Lixian River and Lancang River regions, and the standard deviation of the annual air temperature is also smaller than them. Corresponding to the characteristics of the annual precipitation variations under the effect of the longitudinal range-gorge, the standard deviation of the annual flows of the Yuan River is also obviously greater than western Lixian and Lancang rivers. The barrier action of longitudinal range-gorge on southwest monsoon is greater, but on northeast monsoon is smaller. The annual precipitation variations under the effect of the longitudinal range-gorge are mainly on the smaller time scale, with the increase of time scale, the effect of the longitudinal range-gorge becomes smaller. The role of the longitudinal range-gorge in the annual air temperature variations is smaller than the annual precipitation variations. In recent years, the main characteristics of the annual precipitation variations in all the climatic regions are that precipitation tends to increase, under such an effect, the annual flow variations for the international rivers also tend to be great.