利用COSMIC/GPS掩星折射率资料研究海洋边界层高度的特点

HEIGHT OF ATMOSPHERIC BOUNDARY LAYER TOP AS DETECTED BY COSMIC GPS RADIO OCCULTATION DATA

利用2007—2012年的COSMIC（Constellation Observation System for Meteorology，Ionosphere and Climate）掩星折射率资料，研究全球海洋边界层顶高度的季节变化、年际变化和日变化的气候学特点。结果表明海洋边界层顶有明显的季节和年际以及区域变化特征。就年平均而言，全球海洋边界层顶的水平分布在南北两半球大致呈纬向对称分布，赤道地区的边界层顶最高；由赤道向南北两极边界层顶的高度逐渐降低，其中赤道地区平均高度约为3～3.5 km，副热带地区为2～2.5 km，中高纬度地区为1～1.5 km或以下。海洋边界层顶的日变化幅度较小，一般只有几十米到百米的变化范围，并且日变化特点随地区而有差异，有些地区的最高边界层顶出现在9—12时，另一些地区出现在15—18时。

The characteristics of the atmospheric boundary layer height over the global ocean were studied based on the Constellation Observation System of Meteorology, Ionosphere and Climate （COSMIC） refractivity data from 2007 to 2012. Results showed that the height is much characteristic of seasonal, interannual and regional variation. Globally the spatial distribution of the annual mean top height shows a symmetrical zonal structure, which is more zonal in the Southern Hemisphere than in the Northern Hemisphere. The boundary layer top is highest in the tropics and gradually decreases towards higher latitudes. The height is ina range of 3-3.5 km in the tropics, 2-2.5 km in the subtropical regions and 1-1.5 km or lower in the middle and high latitudes. The diurnal variation of the top height is not obvious, with the height varying from tens to hundreds of meters. Furthermore, it is different from region to region; some regions have the maximum height during 9：00 to 12：00 am, others at 15：00 to 18：00 pro.