基于Copula函数的区域需水量随机模拟

受社会经济发展、气候等因素的影响,区域需水量不可避免存在一定的随机性。鉴于Copula函数可以用来描述事件序列的自相关结构,该文建立了基于Copula函数的区域需水量随机模拟模型。该模型能够考虑各月需水量间的相关性,克服了分离处理各月需水量而导致模拟精度不高的缺点。将模型应用于汉江中下游地区的需水模拟,并与现有的基于Cholesky因子分解模拟模型进行比较,研究了该模型的适用性。结果表明,该模型所模拟需水序列的均值、均方差等统计参数的相对均方误差均较小,同时能够保持各月需水量之间的相关关系,为区域的需水模拟提供了新思路。

Stochastic simulation of regional water requirement based on Copula function

For the factors like socioeconomic development and climate,regional water requirement is random.In view of the fact that Copula function can be used to describe the autocorrelation of event series,stochastic simulation model of regional water requirement is established based on Copula function.This model could reflect the correlation between monthly water requirements,and overcome the disadvantage caused by the simulation of monthly water requirement independently.Taking the middle-lower reaches of Han River as study area,the availability of the proposed model is verified by the comparison between the results of the model and those of Cholesky model.Results suggested that the proposed model can preserve the statistical properties of the calculated data series,especially the skewness coefficient and correlation coefficient,and provide a new way for regional water requirement simulation.