汉江流域气象水文变化趋势及驱动力分析

汉江流域作为南水北调中线工程的水源地，流域水文情势因调水工程和一系列补偿工程发生了重大且长期的调整，分析汉江流域气象水文变化趋势及驱动力对汉江流域水资源的可持续利用和制定合理的水资源管理政策有着重要意义。综合应用Mann-kendall法、累积距平法、降雨-径流双累积曲线法分析了汉江流域近50 a的气象水文资料。结果显示：年降雨量在汉江上游和下游流域呈增加趋势，中游呈减少趋势。年均气温和年蒸发量在全流域呈上升趋势。1965 ~2016年期间汉江上游流域的水资源基本能满足人类活动的用水需求，但汉江中下游流域水资源不足，且人类活动的用水需求在1977年以后一直呈增加趋势。确定汉江流域水文突变年为1990年和2008年，据此划分汉江流域的水文期为基准期，变异Ⅰ期和变异Ⅱ期。采用累积量斜率变化率得出气候波动和人类活动对汉江上游和全流域水文变化的贡献率在变异I期分别为26.1%和73.9%，33.8%和66.2%，在变异Ⅱ期分别为19.3%和80.7%，43.7%和56.3%。人类活动是汉江流域径流变化的主要驱动力，汉江上游的径流受人类活动的影响大于汉江全流域。在变异Ⅱ期，人类活动对汉江上游流域径流影响增加了6.8%，但对全流域径流的影响减少了9.9%。

Trend and Driving Force of Climate and Hydrological Process in Hanjiang Basin

The hydrologic regime has undergone significant and long-term adjustment in the Hanjiang River basin, which is the water head site of Central Line Project of South-to-North Water Diversion. It is key to explore hydrometeorological trends and driving forces for sustainable utilization of water resources and formulation of reasonable water resources management policies. In this paper, the double mass curve method, the accumulative anomaly method and the Mann-Kendall method were used to analyse the hydrometeorological data for the nearly 50 years in the Hanjiang River basin. Results indicate that the annual rainfall in the upper and lower reaches of Hanjiang River shows an increasing trend, but shows a decreasing trend in the middle reaches. Annual average temperature and evaporation increase in the whole basin. From 1965 to 2016, water resources could satisfy the needs for human activities in the upper reaches of the Hanjiang River, while failing those in the middle and lower reaches of the Hanjiang River, despite steady rise in demand since 1977. Two inflection points, 1990 and 2010, were identified, according to which the based period, aberrant period Ⅰ and Ⅱ were divided. Utilizing the slope change ratio of the fitted beeline between year and accumulative quantity, the contribution rates regarding the influence of the fluctuation in climate and human activities on the upper reaches and whole basin is 26.1%, 73.9%, 33.8%, 66.2% in aberrant period Ⅰ, and 19.3%, 80.7%, 43.7%, 56.3% in aberrant period Ⅱ, respectively. The human activities are the main driving force of runoff change, and the effect of that on runoff in the upper reaches of the Hanjiang River is greater than that in the whole basin. In aberrant period Ⅱ, the influence of human activities on the runoff in the upper reaches of the Hanjiang River increase by 6.8%, while that in the whole river basin decrease by 9.9%.