海洋热状况对南海北部局地海雾季节变化的影响

Sea fog is a disaster in the northern South China Sea. It is not only a damage to traffic but also work and lives of people who live nearby the coast. It is an impress of the air-sea interaction in the boundary layer.The warm air with enough water through some processes which make the air saturated and the sea fog occures. The warm wet air and the process could not seperated in the event. This program should be carried out with real time investigation in the first year and get the one year data of the boundary layer. With the data and the function of heat flux,it should illustrate the characteristic of sea fog in the northern South China Sea, and also get the environment factors' character.After analysing the real time data, it gets ready to do some simulation of the sea fog event condition in the northern South China Sea. Do a comparabale research between the real time data and the result of a numerical study of the model called 'weather research and forecasting'. It should improve the WRF model's parameters and do some basic forecasting of the sea fog in the northern South China Sea. And at last, it gives a conclusion of the seasonal variation of sea fog occurred in the northern South China Sea.

南海北部海雾的存在严重影响海上交通和沿海区域人民的生产生活。海雾的产生主要跟海气边界层的环境要素关系密切。海洋上空暖湿空气和让它达到饱和的外界因素都是形成海雾的基础条件。 本课题拟开展南海北部海雾的野外现场观测，获得边界层海气各要素的连续资料，利用块体公式，计算海面热通量。而后进一步分析，阐明南海北部海雾发生频率的季节特征，分析海洋热状况对南海北部局地海雾季节特征的作用。利用Weather Research and Forecasting（WRF）模型对海雾发生时海气边界层参数进行敏感性试验，揭示南海北部海雾发生的机制。

通过WRF模式对海雾发生过程的边界层参数化模拟，冬季南海北部的海雾会出现在两个高压控制的间隙，前期风场的转变和混合使边界层内的水汽得到了充分的增加，在两个高压控制的间隙，弱的下降气流压制边界层的发展，使得边界层高度降低，从而维持了边界层内出现海雾。在海雾发生过程中，大气边界层有很强的梯度层结。.通过WRF模式针对西沙海域出现的一个暖涡过程进行敏感性试验，在不同的海温条件下，分析大气边界层内的气象要素的变化特征，在不同的海表温度条件下，影响的温度和虚位温的变化值局限于大气边界层内，而水汽的增加则可以影响到大气边界层以上。