香溪河初冬降温过程中垂向混合结构特征分析

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...

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

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.