海风发生初期的动力学特征及机理的模拟研究

Land-sea breeze (LSB) occurs at coastal locations throughout the world, and influences weather, climate and environment within a local region. At present, LSB has been studied mainly by field observations and numerical modeling. The basic structures of LSB have been understood and it also has been understood that LSB can produce nonlinear interactions on several scales from meso-scale through turbulent micro-scale. But due to limitation of detecting method, little attention was paid to the procedure and dynamics of sea breeze during the developing period. Further research on this science issue is important to understand the generation and forcastion of sea breeze. In this project, a water tank will be configured based on similarity requirements for simulating convective boundary layer (CBL) and LSB, and model generating and evolving of sea breeze. Two dimensional temperature and velocity fields are recorded using high spatial-temperal resolution instruments, and the trends of some variables about sea breeze can be obtained. So the dynamical characteristics of sea breeze during the developing period and the mechanics of transmission from micro-scale convection to meso-scale circulation can be analyzed. In the meantime, generation and evolution of sea breeze with background wind can be studided using the large-eddy simulation method. Combination of water tank modeling and numerical simulation can do well in studing on the dynamical characteristics and mechanics of sea breeze during the developing period.

海陆风环流发生在海岸地区，遍布全世界，影响局地的天气气候和环境。目前人们主要通过野外观测和数值模拟手段开展海陆风环流的研究，了解了海陆风环流的基本结构，知晓海陆风环流存在着从中尺度到湍流尺度的多尺度的非线性相互作用。但由于研究手段限制，很少关注海陆风发生阶段的过程和动力学特征。该问题的深入研究对于海风发生发展的认识以及海风的准确预报都具有重要的理论意义和应用价值。本项目根据边界层模拟和海陆风模拟的相似性要求设置水槽实验，模拟海风的发生和发展，利用高时空分辨温度速度测量仪器获得二维温度速度场，得到海风发生初期的相关物理量的变化，获得海风发生初期的动力学特征，以及小尺度对流向中尺度演变的机理；同时利用大涡模式对有背景风条件下的海风的发生和发展过程进行数值模拟。通过水槽模拟和数值模拟相结合的方法实现对海陆风环流发生初期的动力学特征及机理的研究。

在本课题的资助下，通过水槽模拟和数值模拟相结合的方法实现对海陆风环流发生初期的动力学特征及机理的研究。根据边界层模拟和海陆风模拟的相似性要求设置水槽实验，模拟海风的发生和发展，利用高时空分辨温度速度测量仪器获得二维温度速度场，得到海风发生初期的相关物理量的变化，获得海风发生初期的动力学特征，以及探讨小尺度对流向中尺度演变的机理；同时利用大涡模式对有背景风条件下的海风的发生和发展过程进行数值模拟，提出了海风启动模型，详细描述了海风启动的过程和海风启动机制。在本课题的资助下，还开展了城市热岛环流和海风环流相互作用的数值模拟研究、海水湍流微结构及其对光传输影响的水槽模拟研究，以及城市近地面层湍流结构和湍流对气溶胶输送特征的实验观察研究。