香溪河初冬降温过程中垂向混合结构特征分析  

Analysis on the vertical mixing structure of Xiangxi River during early winter

作　　者：杨忠勇[1,2] 钱门亮 纪道斌 周哲轩[1] 姚仕明 范中亚[4] YANG Zhong-yong;QIAN Men-liang;JI Dao-bin;ZHOU Zhe-xuan;YAO Shi-min;FAN Zhong-ya(College of Hydraulic&Environmental Engineering,China Three Gorges University,Yichang 443002,China;Three Gorges Reservoir Ecosystem Hubei Province Field Scientific Observation and Research Station,Three Gorges University,Yichang 443002,China;Key Labratory of River Regulation and Flood Control,Ministry of Water Resources,Changjiang River Scientific Research Institute,Wuhan 430010,China;Water Environment Research Center,South China Institute of Environmental Sciences,Ministry of Ecology and Environment,Guangzhou 510665,China)

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443002 [2]三峡大学,三峡水库生态系统湖北省野外科学观测研究站,湖北宜昌443002 [3]长江科学院水利部江湖治理与防洪重点实验室,湖北武汉430010 [4]生态环境部华南环境科学研究所水环境研究中心,广东广州510655

出　　处：《中国环境科学》2021年第6期2862-2870,共9页China Environmental Science

基　　金：国家自然科学基金(U2040220,51779128,52079069,52009066);广东省重点领域研发计划(2020B1111350001)。

摘　　要：基于2018年11月29日~12月15日三峡水库支流香溪河峡口站点的水文气象等实测数据,讨论了香溪河初冬一次典型降温过程中水体的垂向混合结构动力过程,以及水-气界面的热通量和风应力在其中的贡献机制.结果表明,该时段香溪河表层约8m水深范围的垂向混合结构呈显著的日间弱分层,夜间强混合模式,且日间分层时段较短,仅发生在正午前后的约4h内(最大浮力频率约2×10^(-4)s^(-1)).水-气界面的能量输入或耗散过程对水体分层混合过程的贡献显著大于风应力对水体的机械扰动作用.太阳短波辐射是表层水体日间吸热从而分层的主要驱动力,长波辐射在夜间放热过程中处于主导地位,潜热和感热过程在水体放热过程中作用相当.风应力以机械扰动的方式对水体混合模式的影响极小(湍能通量最大值2×10^(-7)m^(3)/s^(3)),主要集中在表层水体约0.5m内,但其可通过影响潜热和感热的方式显著增强中层水体混合特征.由于研究时段香溪河水温较低,蒸发放热较小,而水-气温差相对较大,风应力通过感热驱动的湍能通量(8×10^(-7)m^(3)/s^(3))略大于潜热(7×10^(-7)m^(3)/s^(3)).Based on the measured data of hydrology and meteorology at the Xiangxi River Xiakou site from November 29 to December 15,2018,the vertical mixed structure of the water body during a typical cooling process in the early winter of the Xiangxi River and the heat at the water-air interface were discussed,including the contribution mechanism of flux and wind stress.The vertical mixing structure of Xiangxi River during this period showed significant weak layering during the day and strong mixing at night,and the daytime layering period was quite short,only occurred around noon within 4 hours.The contribution of the energy input or dissipation process at the water-air interface to the stratified mixing process of the water body was significantly greater than the mechanical disturbance effect of the wind stress on the water body.Solar short-wave radiation was the main contribution for the surface water body to absorb heat during the day and thereby stratify the driving force,long-wave radiation was dominant in the heat release process during night.The latent heat and sensible heat processes also played a non-negligible role in the heat release process of the water body.The influence of wind stress on the mixing mode of the water body by mechanical disturbance was mainly concentrated in the surface water body has extremely limited impact on the middle and lower layers,but it could significantly enhance the mixing characteristics of the water body by affecting the latent heat and sensible heat.Due to the low water temperature of the Xiangxi River during the study period,the evaporation heat release was small,and the water-temperature difference was relatively low.Larger,the turbulent energy flux driven by wind stress through sensible heat was slightly larger than latent heat.

关 键 词：香溪河 垂向混合过程 湍能通量 水-气热通量 风应力 

分 类 号：X522[环境科学与工程—环境工程]