在风生混合及水-气之间的热量交换作用下，水体可能出现分层现象，即在其上部形成一种温度、密度均匀的表层混合层，该混合层深度与真光层深度的配置是影响藻类光合作用效率及其种群演替的关键物理过程。太湖在周边地形和适合的气象条件作用下，存在日分层现象且其表层混合层深度变化频繁、空间分异明显；加之底泥再悬浮作用造成真光层深度的空间变化和营养盐的垂直迁移，使得太湖表层混合层深度与真光层深度的配置对藻类生长的影响较海洋或深水湖泊更为突出。然而在太湖中，针对该配置对藻类生长影响的研究相对甚少。本研究拟通过模拟高时空分辨率的气象要素场作为驱动场，利用非结构有限元的斜压动力模式，对水体三维水温进行模拟，并由此分析表层混合层深度的时空变化规律，同时通过同步的野外观测确定真光层深度和藻类初级生产力廓线，以研究太湖表层混合层深度与真光层深度的配置对藻类生产力的影响规律，该研究为大型浅水湖泊的水环境治理和修复奠定基础。

With the combination effect of the wind-induced mixture and the heat exchange between air and water, the thermal stratification may be appear, which means that the surface mixed layer might establish in the upper layer. The water temperature and density in mixed layer is vertically homogenized. The ratio of the surface mixed-layer depth to the euphotic depth is a key physical factor which influences algal photosynthesis efficiency and the succession of the phytoplankton. Under the effect of the surrounding terrain and the suitable meteorological fields, there exits diurnal stratification in Taihu Lake where the surface mixed layer depth varies frequently and its spatial distribution is remarkably different. Additionally, due to the spatial difference of the euphotic depth and the vertical transportation of nutrients, which are caused by sediment resuspension, the ratio of the surface mixed layer depth to the euphotic depth influences greatly on the algae growth in seas and deep lakes.But the study on that influence is very little so far in such large and shallow lakes as Taihu Lake. Based on the driving fileld originated from the high spatial-temporal resolution of the meteorological data, the baroclinic dynamic model with unstructured grid and finite element method would be used to simulate the three-dimensional water temperature, and the spatial-temporal variation law of the surface mixed layer depth would furthur analyzed. At the same time, the euphotic layer depth and the profile of the algal primitive productivity were synchronously observed to explore the law of the influence of the ratio of the surface mixed-layer depth to the euphotic depth on the algal primary production. The study on Taihu Lake would be helpful for the improvement of the aquatic ecological environment in large shallow lakes.