热带西太平洋边界层的多层结构分析

The Analysis of Multiple-Structure of the Atmospheric Boundary Layer in the Western Tropical Pacific Ocean

本文主要利用第一次“中美热带西太平洋海气相互作用联合调查”所获得的海洋水文、气象及大气探测资料,分析了热带西太平洋暖水区边界层大气层结特征,指出热带西太平洋边界层大气具有多层结构和多层送温现象,边界层内各层厚度及气温、位温、混合比随高度的变化趋势如下:超绝热层位于地面以上50m左右,气温、位温、混合比迅速减小,系绝热不稳定层;第一层为混合层,平均厚度为351m,位温、混合比变化不明显;混合层上又是逆温层大多为30—100m厚,位温迅速增大,混合比迅速减小,系绝对稳定层;700—1000m为浅对流云活跃层,气温缓慢减小。

The atmospheric stratification features of the boundary layer above the warm pool of the western tropical pacific are analyzed with the hydrographical and meteorological data obtained during the First Cruise of USA/PRC Joint Air-Sea Interaction studies. The results show that the atmospheric boundary layer over the western tropical pacific is multiple-structured with multiple temperature inversion layers. The thickness, temperature, potential temperature and mixing ratio in each sub-layer are as follows : the thickness of the superadiabatic layer is about 50m. In this layer the temperature, potential temperature and mixing ratio decrease rapidly with height. Therefore, it is an adiabatically unstable layer. There is a mixing layer above the superadiabatic layer with a thickness of 351m, in which the potential temperature and mixing ratio do not change much. The temperature inversion layer above the mixing layer is an absolutely stable layer with a thickness of 30 - 100m, in which the potential temperature ircreases rapidly with height and the mixing ratio decreases. At the height of 700 - 1000m, there is a shallow layer of convective clouds, in which the temperature decreases gradually with height.