1951—2007年墨累-达令流域水文气象要素演变

Evolution of Hydrometeorological Elements in the Murray-Darling Basin from 1951 to 2007

墨累-达令流域是澳大利亚最大的河流系统,其干旱与水资源短缺的现象日益严重。因此,探讨该区域径流与降水、气温的长期演变规律具有重要意义。选取该流域的代表性站点,采用M-K检验、小波分析和小波相干性分析等方法研究了1951—2007年间其气温、降水和径流的演变趋势及时频特征,并分阶段研究了此三要素的阶段性变化特征及降水-径流响应关系。结果表明:1951—2007年间,研究区域的气温显著升高,降水量呈不显著下降趋势,而径流深呈显著下降趋势且在2002年发生突变。径流深存在5、22年左右的主周期;气温存在12、24年左右的主周期;降水量存在5、22、33、40年左右的主周期。在整个时间域上,径流深与降水量存在很好的正相关关系,而径流变化滞后于气温变化,呈非线性负相关关系。将所研究的时段1951—2007年划分为3个阶段:墨累-达令流域委员会成立前为第1阶段(1951—1988年);从1989年到径流时间序列发生突变的年份为第2阶段(1989—2002年);从2002年到序列资料终止年份为第3阶段(2003—2007年)。不同阶段降水-径流关系差异明显,第3阶段的产流量显著降低,说明非降水因素对河川径流量的变化具有重要影响。

The Murray-Darling Basin is the largest river system in Australia,and its drought and water shortage are becoming more and more serious.Therefore,it is of great significance to explore the long-term evolution law of runoff,precipitation and temperature in this region.Based on the M-K test,wavelet analysis and wavelet coherence analysis,the evolution trend and time-frequency characteristics of temperature,precipitation and runoff in the basin from 1951 to 2007 are studied.The phase change characteristics of these three elements and the precipitation and runoff response relationship are studied in stages.The results are as follows.From 1951 to 2007,the temperature in the study area increased significantly,the precipitation showed an insignificant downward trend,while the runoff depth showed a significant downward trend and a sudden change occurred in 2002.The main cycle of runoff depth is about 5 and 22 years.Temperature has a main cycle of about 12 and 24 years.Precipitation has a main cycle of about 5,22,33 and 40 years.In the whole time domain,there is a good positive correlation between runoff depth and precipitation.The change in runoff lags behind the change in temperature,showing a non-linear negative correlation.The study period from 1951 to 2007 is divided into the following three stages.The first stage(1951 to 1988)starts from 1951 to the establishment of the Murray-Darling Basin Commission.The second stage(1989 to 2002)is from 1989 to the year when the runoff time series mutated.The third stage(2003 to 2007)is from 2002 to the year when the series data ended.The relationship between precipitation and runoff at different stages is significantly different,and the discharge in the third stage is significantly reduced,indicating that non-precipitation factors have an important impact on the changes in river runoff.