摘要
利用2007—2012年的COSMIC掩星折射率资料,结合改进的折射率断点法,分析了全球海上边界层高度的季节、日变化特征,并引入尖锐系数对结果进行了评估。边界层高度大值区水平分布呈纬向不对称,中低纬度地区的几个区域边界层最高,由赤道向南北两极递减。在副热带高压控制的部分地区,边界层高度季节变化不明显,而在大陆西海岸的盛行层状云地区,表现出一定的季节变化特征。边界层高度的日变化相对较弱,并且在不同地区略有差异。尖锐系数的评估结果表明:尖锐系数在亚热带最大,折射率断点法能获取准确的边界层高度,而在赤道辐合带和南太平洋辐合带最小,边界层高度定义相对模糊。
Based on the COSMIC occultation data from 2007 to 2012, combined with the improved refractive breakpoint method, the seasonal and diurnal variation characteristics of the global maritime boundary layer height were analyzed. Fourthermore, the analysis results were also evaluated by sharpness coefficients. High boundary layer approximately distributes in an asymmetric zone, and in several regions of the low and middle latitudes there is the highest boundary layer, the height gradually decreased from the equator to the north and south poles. In some regions covered by the subtropical high, the seasonal variation of boundary layer height was not obvious, while in the area of the west coast of the mainland where the stratiform cloud is prevalent, there is some seasonal variation characteristics.The diurnal varia- tion of the boundary layer height is relatively weak and is slightly different in different areas. The evalua- tion of the sharpness coefficients shows that the largest sharpness coefficient appears in the subtropical zone, and the refractive breakpoint method can provide accurate boundary layer height in the area, while in the equator convergence zone and the South Pacific convergence zone, the minimum sharpness coeffi- cient makes the definition relatively fuzzy.
出处
《气象科学》
北大核心
2015年第6期737-743,共7页
Journal of the Meteorological Sciences
基金
国家自然科学基金资助项目(41405025
41475021)
江苏省自然科学基金资助项目(BK20140064)
关键词
COSMIC
边界层高度
季节变化
日变化
COSMIC
Boundary layer height
Seasonal variation
Diurnal variation
