基于GAMLSS 模型的宜昌站年径流序列趋势分析

在变化环境下, 研究非一致性水文序列的变化趋势具有重要意义。常规的趋势分析方法一般只能分析水文序列均值的线性趋势。本文引入GAMLSS模型对宜昌站1882-2009 年间的年平均流量序列和年最小月流量序列分别进行趋势分析, 将序列的趋势分析从均值扩展至均方差(或变差系数)、偏态系数等其他统计参数。研究发现宜昌站年平均流量序列的均值有明显线性减少的趋势, 而宜昌站年最小月流量序列线性趋势不明显。在此基础上, 建立基于多项式回归的GAMLSS模型, 结果表明宜昌站年最小月流量序列并非平稳序列, 其均值表现为非线性的趋势变化, 偏态系数呈现线性的趋势变化。

Trend Analysis for the Annual Discharge Series of the Yangtze River at the Yichang Hydrological Station Based on GAMLSS

It is very important to study the trends of the inconsistent hydrological series under the changing environments. The conventional methods of trend analysis can only be used to analyze the linear trends of the mean value of hydrological series. In this paper, GAMLSS is introduced to analyze the trends in both the annual average discharge series and the annual minimum monthly discharge series of the Yangtze River at the Yichang hydrological station. GAMLSS can detect not only the time variation of the mean value of the discharge series, but also the time variation of other statistical parameters, such as standard deviation (or coefficient of variation) and coefficient of skew. Model results indicate that the mean of the annual mean discharge series decreases linearly with time, and the annual minimum monthly discharge series do not show any significant linear trend of decrease or increase.