Study on Response to Mechanical and Thermal Disturbances of Waterry Environment in Standing Water Areas

研究了浅水区水体温度和溶解氧垂直结构对水面扰动的响应，探讨了浅水区水体温度和溶解氧垂直结构与水质和污染控制的关系。扰动包括热力扰动和机械扰动，即太阳加热和冷却的日循环以及风应力引起的混合和环流.本文研究了风诱导楔形内层，它形成于水域迎风面，控制着通过密度界面从下层到上层的垂直质量传递.当垂直方向一维风致混合显著时，楔形层尺度依赖于一个总的Richardson数，楔形层内密度随时间呈指数变化，楔形层的膨胀和收缩速率由密度界面上的幂函数表示.研究发现，垂直溶解氧剖面对热力层结和热力混合层的生长有敏感的响应，并受表层复氧和风致混合的共同控制.利用实测水温剖面资料，通过一维热扩散方程在垂直方向上的估算，得到了垂直热力涡动扩散率剖面的变化规律.

Response of water temperature and dissolved oxygen vertical structures caused by disturbances added to the water surface, which were concerned with water quality and pollution control in shallow standing water areas, were studied. Disturbances are thermal and mechanical, which are the daily cycle of solar heating and cooling and the mixing and circulation due to wind stress.Wind induced wedge shaped internal layr, which was developed at the windward in the water area and governed vertical mass transfer from lower to upper layr through the density interface, was investigated. When one dimensional wind induced mixing in the vertical direction was remarkable, the wedge shaped layr scale depended on an overall Richardson number, the magnitude of density in the wedge varies exponentially with time and the expansion and contraction rate of the wedge was prescribed by entrainmentrate through the density interface.The dissolved oxygen (DO) daily cycle behaviors due to two disturbances was investigeated from field observation. It was founded that the vertical DO profile was sensitively responsed to thermal stratification and thermal mixing layr growth and was governed both reaeration at the surface and wind induced mixing.Using field data on the water temperature profiles with time to disturbances, variations of vertical thermal eddy diffusivity profiles were founded by means of estimating fromone dimensional thermal diffusion equation in the vertical direction.