基于Copula的降水量不确定性建模
Assessing the Local Uncertainty of Precipitation with Copulas
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摘要: 传统的地统计学方法需要区域降水量满足多元正态假设才能给出无观测站位置降水量的概率密度函数,经典的统计学方法则用唯一的概率密度函数对区域内任一无观测站位置的降水量进行统计描述。尝试用基于Copula的地统计学方法对无观测站位置月降水量的不确定性进行建模,并与上述两种方法进行对比分析。案例研究表明,基于Copula的地统计学方法可以得到任一无观测站位置的概率密度函数,且不同位置的概率密度函数与其周围观测站的分布及其观测值有关率优于普通克里格和基于Box-cox变换的普通克里格。Abstract: The traditional geostatistical model requires regional precipitation fulfills assumption of mul-tivariate normal distribution in order to estimate the probability density function(PDF)of any un-gauged location.And the classical statistical model describes precipitation of any ungauged location u-sing only one PDF.The study attempted to use copula-based geostatistical technology to model the un-certainty of monthly precipitation at any ungauged location and compare it with the above two meth-ods.A case study showed that Copula-based geostatistical model could get the PDF of any ungaugedlocation,which not only depended on the density of the observation network,but also on the magni-tude of the measurements and the coverage of cross-validation confidence intervals was better than thatof the ordinary Kriging and ordinary Kriging with Box-Cox transformation.