西江下游年月径流变化特征研究

Characteristics of Annual and Monthly Runoff Variation in Xijiang River Basin

采用Mann-Kendall法、滑动T检验法、R/S分析法和小波分析法分析西江下游梧州水文站1950年至2015年径流的趋势性、变异性和周期性等特征及年内径流变化趋势表明,其年平均流量66a来呈不显著减少趋势,并在未来一段时间内保持持续减少趋势;从累积距平看2014年后8~10a,西江径流将处于递增阶段;年内径流变化则呈蓄峰补枯的良好趋势,但7月月径流呈递增趋势值得关注;年径流在1954年发生中度变异,2002年为转折突变点,无明显变异;西江径流存在22a、15a、5a这3类尺度的周期变化;预测2015年~2020年前后,西江下游径流在22a尺度上将处于偏枯期,而在15a尺度下为相对偏丰期。

The Mann-Kendall method, sliding T-test method. R/S analysis method and wavelet analysis method are used to analyze the mutations, trends and periodicity characteristics of the runoff from 1950 to 2015 in Wuzhou Hydrological Station in the lower reaches of Xijiang River and the trend of monthly runoff change. The results show that, （a） the annual average flow of 66a has no significant decreasing trend, and will keep decreasing trend for a period of time in the future; （b） from the point of accumulated anomalies, the runoff of Xijiang River will be in an increasing phase from 8 to lOa after 2014; （c） the annual variation of inner diameter flow is a good trend of peak filling and dry feeding, however, the monthly runoff only in July is on the rise which is worth paying attention to; （d） annual runoff occurs moderate variation in 1954, and turning point in 2002 with no significant variation, and （e） according to the Morlet wavelet analysis, there are 3 time scale periodic variations such as 22a, 15a and 5a. It is predicted that the runoff in the lower reaches of Xijiang River will he in a dry period in 22-year-scale but in a wet period in 15-year-scale during 2015-2020.