长江中游荆南三口河系径流演变特征及趋势预测

以荆南三口五站1951~2015年实测径流数据,利用Mark-Kendall趋势突变检验法、累计距平、Morlet复小波等方法分析三口河系径流演变特征;选用ARIMA模型和时间序列模型预测荆南三口河系径流演变趋势。结果表明:(1)荆南三口径流年际变化较大,径流年内分配不均匀,5~10月为丰水期,11月~次年4月为枯水期,呈现出明显季节差异;(2)三口径流总体上呈下降趋势,其中以1959~1980年径流下降趋势最为明显,其趋势幅度p的绝对值达到了698.313,2003~2015年径流下降趋势较为缓慢,无明显趋势,但其p的绝对值仍达到了166.524;(3)运用Mark-Kendall突变检验及累计距平法共同检验,三口径流突变年份为1970年、1985年;(4)1951~2015年间三口径流变化过程主要存在48~58 a、20~28 a、10~18 a 3个尺度的周期变化,以55 a、24 a、14 a为周期中心,其小波方差显示三口径流序列第一、第二、第三主周期分别为55 a、24 a、14 a;(5)三口径流在2016~2030年呈现出先减小后增大的趋势,即2016~2018年为波动增减期,2019~2026年前后为枯水期,2026~2030年为丰水期。

RUNOFF'S EVOLUTION CHARACTERISTICS AND FUTURE TRENDS IN THE THREE OUTLETS ALONG SOUTHERN JINGJIANG RIVER OF MIDDLE REACHES OF CHANGJIANG

Upon the 1951-2015 observation runoff data of the five stations in the Southern Jingjiang River section (of the Yangtze River),the present study analyze the section historical runoff evolved characteristics through the methods of Mark-Kendall Test,Cumulative Anomaly,and Complex Morlet Wavelet Transform,respectively;this study also forecast the future period (2016-2030) runoff changing scenario with the ARIMA model and Time series model.The results show that:(1) Historical annual runoff of this section changed greatly with large discrete degrees,and exhibited significantly seasonal variations,the dry season covered between each November and next April,but the wet season distributed unevenly in other 6 months;(2) This section historical runoff presented a general declining trend over the past 65 years.The largest runoff declining period was 1959-1980 and the trend magnitudes absolute value p was 698.313.The Mark-Kendall test showed there were no obvious runoff changes in the period of 2003-2015,but the trend magnitudes absolute value p also reached 166.524;(3) The Mark-Kendall test and the Cumulative Anomaly results showed the sudden change year of this section runoff was 1970 and 1985,respectively;(4) Over the past 65 years,the river section runoff presented three main changing periods,48-58 a,20-28 a,and 10-18 a,respectively;the wavelet variance showed the order of three main changing periods was 55 a (first),24 a (second),and 12 a (third),respectively;(5)This section forecasted future (2016-2030) runoff will be decreased earlier and increased later relative to current conditions,which mean 2019-2026 may be dry period,and 2026-2030 may be wet period,respectively.