热带海气边界层观测研究若干进展

Advances in Tropical air-sea boundary layer observations

  • 摘要: 热带海洋大气边界层在各种尺度的海气相互作用过程中占有非常重要的地位,随着海洋上观测系统的不断发展,关于海洋大气边界层的研究取得了较大的进展。在对近10年来热带海气边界层观测研究调研的基础上,介绍了热带气旋强风天气条件下通量交换特征、湍流谱特征和边界层急流的主要研究进展。近年来的研究结果显示:在强风条件下,海面拖曳系数在风速增大到某一数值后,不再随风速增大而增大;在热带气旋的边界层内存在低空急流,但是不同的研究工作中低空急流高度不一致。同时介绍了我国低纬度地区两种常见的天气系统海雾和南海季风背景下湍流和边界层观测的研究成果,海雾边界层研究结果显示:南海海雾与我国高纬度地区东海、黄海的海雾在大气边界层结构方面有着明显的差异,其生成机理也有所不同;西南季风系统对我国的天气气候影响非常大,研究表明季风爆发前后的通量和边界层结构有着自身的特点。由此可以发现,不同的天气系统下,海洋大气边界层的通量交换和边界层结构不同,使得我们在研究海气相互作用时要分别对待,同时海气耦合模式的边界层参数化研究要有一定的针对性。最后提出我国未来的热带海洋气象观测应以点(观测站点)面(卫星)观测相结合,获取不同天气条件下的界面通量交换和大气边界层特征,以改进和完善数值预报模式,提高海洋气象预报服务能力。

     

    Abstract: The tropical marine atmospheric boundary layer has a very important role to play in various scale air-sea interaction processes. With the development of ocean observing systems, the research on the air-sea boundary layer has made a great deal of progress. This paper reviews the main progress of the tropical air-sea boundary layer observational studies over the past decade, which is the research of flux exchange characteristics, turbulence spectrum characteristics and boundary layer jet under the tropical cyclone high wind conditions. The study results show that the value of the drag coefficient at sea surface is not magnifying with the wind speed increasing when the wind reaches the value in strong wind conditions. And the results also illustrate that there is a low-level jet in the tropical cyclone boundary layer, but the jet height is not consistent in different research work. Meanwhile, the observational studies on the turbulence and boundary layer structure are proposed in two common weather systems such as sea fog and the South China Sea Monsoon over the low latitudes areas of China. The results show that the South China Sea fog is different from the East China Sea fog and Yellow Sea fog over high latitude regions in the atmospheric boundary layer structure and the generation mechanism of sea fog. The summer monsoon system has a great impact on the weather and climate in China. Studies have shown that the flux and boundary layer structure before or after the monsoon onset have their own characteristics. It is found that the flux exchange and boundary layer structure of the marine atmospheric boundary layer are different under different weather systems, so that these characteristics should be treated separately in the study of air-sea interaction, and boundary layer parameterization of air-sea coupled model should be targeted. Finally, in order to improve and refine numerical prediction model, a proposal of tropical marine meteorological observations is put forward, which will be the point (observation site) combined with surface (satellite) observations to explore the air-sea interface flux exchange and atmospheric boundary layer characteristics in the various weather conditions. And then the marine weather forecasting service capabilities will be further improved by these studies.

     

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