金沙江下游径流丰枯频率分析

以金沙江中游小得石站1953～2004年径流资料及宜宾市1953～2004年月平均降水资料为基础，应用Copula函数构造径流量和降水量的联合分布，对金沙江下游径流的丰枯频率进行分析。结果表明：各季度的降水量和径流量均服从皮尔逊Ⅲ分布；Clayton Copula函数能很好地拟合各个季度降水量和径流量的联合分布；各季度的丰水频率分别为14.08%、18.11%、12.32%、13.01%，对应的枯水频率分别为15.51%、18.78%、14.16%、15.48%。上述研究能够为金沙江下游水资源的合理调度提供科学依据，也能为进一步的风险评估奠定基础。

Study on analysis of frequency of higher and lower runoff in Lower Jinshajiang River

Based on the data of the annual runoff from 1953 to 2004 obtained at Xiaodeshi Hydrological Station located at the Mid Jinshajiang River and the monthly mean precipitation data from 1953 to 2004 got from Yibin Hydrological Station，the frequency of higher and lower runoff in Lower Jinshajiang River is analyzed herein with the joint distribution of both the precipitation and runoff constructed with Copula function. The result shows that the precipitations and runoffs within all the quarters are accorded with the Person type Ⅲ distribution and the joint distributions of the precipitations and runoffs within all the quarters can be better fitted by Clayton Copula function; while the frequencies of abundant water of all the quarters are 14.08%、18.11%、12.32%、13.01%respectively and the corresponding dry frequencies are 15.51%、18.78%、14.16%、15.48%respectively. The study mentioned above can not only lay a scientific basis for the reasonable allocation and control of the water resources of the Lower Jinshajiang River，but can also build a foundation for the further risk assessment.