年径流频率分析的一次二阶矩法及其应用

Derived moment approach for analyzing the annual runoff frequency and its application

针对流量资料极短时传统年径流频率分析方法——适线法不再适用的问题,分析了基于水文过程,由影响径流形成的因子推求年径流频率的一次二阶矩法的可行性,并讨论其在无流量资料流域应用中所存在的问题与解决方法。以江西省20个流域为研究对象,采用无参数Schreiber方程与单参数Fu-Zhang方程的水量平衡式作为年降雨—径流模型,结果表明:(1)一次二阶矩法的分析结果与实测年径流的经验频率较为吻合;(2)无流量资料流域中,忽略土壤含水量年间变化的作用,Fu-Zhang模型的分析结果比Schreiber模型好;(3)无流量资料流域中,FuZhang模型中的参数ω可采用反距离权重法估计。

The current work confirms that the derived moment approach is a suitable replacement for the curve fitting method when runoff data are not readily available. Specifically, annual runoff frequency was estimated using climate variables associated with hydrological processes. The difficulties involved in assessing the annual runoff frequency in the ungauged basins and the solutions to these problems are discussed. Here, 20 basins in Jiangxi Province were ex- amined using the two annual rainfall--runoff models established based on the Schreiber equation and Fu-Zhang equa- tion. Three relevant conclusions were drawn. First, the frequency distributions of annual runoff estimated using the de- rived moment approach fit the empirically observed frequency of the annual runoff perfectly. Second, the Fu-Zhang model was found to perform better than the Schreiber model when the basins＇ interannual changes in soil moisture con- tent were not known. Finally, the parameter oJ in the Fu-Zhang model was estimated using the inverse distance weight interpolation method through the calibrated value to of neighboring basins whose runoff data were available.