汉江流域降水、蒸发及径流长期变化趋势及持续性分析

分析汉江流域降水、蒸发、径流等水文要素长期变化趋势是开发利用汉江水资源、研究人类活动对江汉流域生态环境影响的前提。基于汉江流域13个水文站1960～2003年逐月降水量、气温观测资料,采用高桥蒸发模型计算了汉江流域年径流量,采用Mann-Kendall非参数检验法分析了该流域降水量、蒸发量、径流量的变化趋势,并由Hurst指数分析了各水文要素变化趋势的可持续性。结果表明,采用高桥蒸发模型间接计算年径流量适应性较强,值得推广;汉江上游多数站点年降水量减少,下游站点年降水量增加,且变化趋势不显著;上游站点年蒸发量增加趋势显著,其余站点变化趋势不显著;上游多数站点年径流呈不显著减少状态,下游钟祥、天门和武汉站径流呈不显著增加状态;各站点水文要素均具有很强的持续性,降水、蒸发、径流的常数C分别为0.73、0.95、0.97。

Long term Variation Trend and Sustainability Analysis of Precipitation, Evaporation and Runoff in Hanjiang Basin

Long-term variation trend analysis of hydrological element in Hanjiang basin including precipitation,evaporation and runoff is the precondition of development and utilization of water resources,and study of the impact of human activities on ecological environment.Based on the observed monthly precipitation and temperature data of 13 survey stations from 1960 to 2003 in Hanjiang basin,the annual runoff is calculated with Takahashi Koichiro’s evaporation model.And nonparametric Mann-Kendall method is used to detect long-term variation trend of precipitation,evaporation and runoff.Then the Hurst exponential method is applied to analyze the trend persistence of hydrological elements.The results show that Takahashi Koichiro’s evaporation model has strong adaptability for annual runoff calculation and it is worth promoting;the annual precipitation in the upper reaches of the Hanjiang basin appears downward trend while it is upward trend in the lower reaches;for annual evaporation,it appears significant upward trend in the upper reaches;for annual runoff,the upper reaches appears downward trend but Zhongxiang,Tianmeng and Wuhan station appear upward trend;for hydrological elements,persistence trend is strong and the constant C of precipitation,evaporation and runoff is 0.73,095,0.97,respectively.