基于静止卫星的青藏高原及周边地区夏季对流的气候特征分析

The climatic characteristics of summer convection over the Tibetan Plateau revealed by geostationary satellite

中文关键词:  青藏高原  黑体亮度温度  对流  强对流

英文关键词:Tibetan Plateau  TBB  Convection  Severe convection

中文摘要:

      利用2010-2014年静止气象卫星FY-2E的红外TBB资料，分析了夏季青藏高原（高原）及周围地区对流的气候特征。分析表明，5月，高原最主要的对流发生在东部边缘。6月，随着亚洲夏季风爆发，最强的对流（强对流）发生在高原的东南侧。7-8月，强盛的西南风给高原中东部部分地区带来丰沛的水汽，高原的东南部形成一条对流（强对流）活跃带。在高原西部，对流发生频率大于6%的区域出现在西部南麓的时间约为37候，并于7月底-8月初到达最北。在高原中部，对流（强对流）开始活跃的时间为6月上旬（中旬），维持整个盛夏，并分别经历3次向北推进，最北约到达34°N。在高原东部，5月底开始对流都处于相对活跃期，有3次（两次）对流（强对流）的北进。高原对流（强对流）发生频率存在两个季节内变率大值区，分别位于高原中南部雅鲁藏布江中段和高原东南部西藏、青海、四川三省交界处。对流发生频率的第一模态主要是高原东南部和南部的印度季风区对流的反向模态，第二模态则体现了高原西部和印度大陆80°E以西地区与南亚大陆80°E以东地区的对流发生频率的三极型变化。

英文摘要:

      Based on the infrared TBB of the geostationary meteorological satellite FY-2E from 2010 to 2014, the climatic characteristics of summer convection over the Tibetan Plateau and its surrounding areas are analyzed. The analysis shows that in May, the main convection occurs in the eastern edge of the Tibetan Plateau. In June, following the onset of the Asian summer monsoon, the strongest convection (severe convection) occurs in the southeastern part of the Tibetan Plateau. In late summer, strong southwesterly winds transport abundant moisture to the eastern and central areas of the Tibetan Plateau, leading to the formation of an active convection belt in the southeastern part of the Tibetan Plateau. In the western plateau, the area with convection frequency greater than 6% reaches the southern plateau at about the 37th pentad, and gradually moves northward until the end of July. In the central plateau, convection (severe convection) becomes active since early (mid) June, and maintains over the entire late summer with three major northward movements until reaching 34°N. Convection in the eastern part of the Tibetan Plateau is relatively active since the beginning of May and its northward stretching time is slightly later than that over the central plateau. Two high intra-seasonal variability centers are located in the middle branch of the Brahmaputra and the southeastern part of the plateau. Summer convective activities are unevenly distributed in these regions, which are prone to drought and flood disasters. The first leading mode of the convection frequency is the reverse mode of that in the Indian monsoon region and the southeastern part of the plateau while the second leading mode reflects the tripole variation pattern over the western part of the plateau,the India continent west of 80°E and the South Asian continent east of 80°E.