研究葛洲坝下游江段水温变化的影响因素及其贡献将有助于水生态水温变化本质的认识,对中华鲟产卵场保护亦具有重要意义.结合一维水流水温数学模型、热量收支平衡分析等手段对上述问题进行了初步探讨.初步研究结果表明:葛洲坝坝下江段水温主要受三峡水库水气界面热交换影响,寸滩来流、三峡大坝泄流以及葛洲坝电站运行等因素影响相对较小.从全年看,三峡工程运行前后库区水温变化均由净辐射和蒸发热起主导作用,但三峡工程运行后热传导热量比重有较大增加.三峡工程运行前后,11月份水温均由水气界面热传导起主导作用,但随着三峡水库蓄水位抬高,辐射量和蒸发热量所占比重显著增加,而热传导、寸滩来流和三峡大坝泄流热量所占比重逐渐减小.三峡水库的不同运行过程将影响各热量来源对库区水温变化贡献大小,进而影响葛洲坝坝下江段水温.%Researches on the influencing factors of water temperature variation near downstream Gezhouba dam would be conducive to understand the nature of water temperature variation,and is of great significance for the protection of Chinese sturgeon spawning grounds.In the present research,one-dimensional mathematical model of water flow and temperature together with the overall heat budget balance is adopted to preliminarily research this issue.Results reveal that the water temperature near downstream Gezhouba dam is mainly affected by the water temperature in the Three Gorges Reservoir; while other factors such as the inflow heat from Cuntan,the outflow heat from Three Gorges Dam and the operation mode of Gezhouba hydropower station have relatively less impacts.To be specific,net radiation heat and vaporization heat dominated the yearly variation of water temperature in the reservoir both before and after the operation of TGP,but the contribution of air-water heat conduction increased remarkably after the TGP operation.In November,particularly,heat conduction was the main influencing factor before and after TGP,but after the operation of TGP with the raising of impoundment level,the proportion of radiation heat and vaporization heat increased obviously,whereas heat conduction,inflow heat from Cuntan,and outflow heat from Three Gorges Dam gradually weakened.The operation of TGP have impacts on the contribution of each factor,hence affecting the water temperature in downstream Gezhouba dam.
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