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

研究了与浅水静水水质和污染控制有关的水面扰动对水温和溶氧垂向结构的影响。扰动是热的和机械的，主要是太阳加热和冷却的日循环以及风应力引起的混合和环流。研究了风致楔形内层，它是在水域的迎风方向发展起来的，通过密度界面控制从下层到上层的垂直质量传递。当一维垂直方向风致混合显著时，楔形层尺度依赖于总的Richardson数，楔形层的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的夹带率决定。结果表明，垂向溶氧廓线对热力层结和热混合层生长反应敏感，受表层复氧和风致混合影响，利用现场水温廓线资料，从垂直方向一维热扩散方程出发，建立了垂向热涡扩散系数廓线的变化规律。

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.