基于变点识别的区域河川径流量特征值变异研究

基于变点原理,运用最大似然比和西沃兹信息标准方法,对广东省4种径流量序列进行均值变点和方差变点的识别,研究存在变点的河川径流量序列、时间位置、空间分布及变点后的特征值变化状况,以揭示广东省河川径流量时空变异特点。结果发现:广东省河川年径流量和汛期径流量序列的一致性较好,而枯期径流量和最小月径流量序列的特征值变点具有普遍性,年均值明显增加,年际离散程度增大,时间位置主要为1972-1973年和1981年两个时间段。枯期径流量序列均值变点的典型地区主要为东江流域,方差变点的典型地区主要为北江流域、韩江流域、粤西地区和珠江三角洲;最小月径流序列主要为均值变点,典型地区有东江流域、韩江流域;而北江入珠江三角洲的河川径流量变异尤其典型,4种径流序列均存在均值变点和方差变点。

Characteristics Variability Study of Regional River Runoff Time Series Based on Change Point Recognition

River runoff is a significant assessment index for surfer water resources. In this paper, based on the change-point theory and methods, the likelihood ratio method testing in the mean and the Schwarz Information Criterion testing in the variance, change points of time series of the river runoff such as the full year runoff, the flood season runoff, the dry season runoff, and the least monthly runoff are recognized for the main gauge stations of Guangdong Province from 1957 to 1999(hydrological year). Temporal and spatial locations of these tested change points are described in detail and key features of the characteristics variability of time series of the river runoff are concluded on the whole. In general, it is found that change point is widely tested in the existence of the dry season runoff and of the least monthly runoff, which annual runoff increases significantly and fluctuates remarkably after the change-point time, otherwise of the full year runoff and of the flood season runoff, and the change point location of these stations obviously occurred in 1972-1973 and 1981. Furthermore, change point in the mean of the dry season runoff happens in the Dongjiang Basin, and change point in the variance in the Beijiang Basin, the Hanjiang Basin, the Western Guangdong, and the Pearl River Delta. Change point in the mean of the least monthly runoff presents in the Dongjiang Basin and the Hanjiang Basin. Particularly, change point in the mean and in the variance are tested in the existence of these four kinds of annual series in the Sanshui station, the controlling gauge station of the Beijiang River flowing to the Pearl River Delta.