Intraseasonal Variations of Summer Convection over the Tibetan Plateau Revealed by Geostationary Satellite FY-2E in 2010-14
Intraseasonal Variations of Summer Convection over the Tibetan Plateau Revealed by Geostationary Satellite FY-2E in 2010-14
复制标题
静止卫星FY-2E揭示的2010-14年青藏高原夏季对流的季节内变化
DOI：
10.1007/s13351-019-8610-3
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发表时间：
2019
影响因子：
3.2
通讯作者：
Tang Shihao
中科院分区：
文献类型：
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作者：
Li Bo;Yang Liu;Tang Shihao
基于2010 - 2014年FY-2E卫星红外黑体温度（TBB）观测资料，分析了青藏高原及周边地区夏季对流的季节迁移、发生频率和季节内变率。结果表明：5月对流主要发生在青藏高原东缘；6月，随着亚洲夏季风的爆发，太平洋东南部出现最强（强）对流；7 - 8月，强烈的西南风向青藏高原东部和中部输送了丰富的水汽，导致青藏高原东南部形成了活跃的对流带。在青藏高原西部，37候前后对流频率大于6%的区域占据南部高原，并逐渐北移至7月底；在高原中部，对流（强对流）从6月上旬（中旬）开始活跃，并持续到整个夏末，有三次主要的北移，直到到达34 N；青藏高原东部自5月初以来对流相对活跃，向北伸展的时间稍晚于高原中部。总体而言，青藏高原夏季对流活动分布不均匀，对流频率自南向北递减；在雅鲁藏布江中游和东南高原地区表现出较大的季节变化。青藏高原夏季对流频率的EOF分析揭示了两种主导模态，第一模态为印度季风区与青藏高原东南部之间的偶极子变化型，第二模态为青藏高原西部、80 E以西的印度大陆和80 E以东的南亚大陆上空的三极子变化型。
Based on the infrared black body temperature (TBB) observed by the geostationary meteorological satellite FY-2E from 2010 to 2014, the seasonal migration, occurrence frequency, and intraseasonal variability of summer convection over the Tibetan Plateau (TP) and its surrounding areas are analyzed. The results show that in May, convection mainly occurs over the eastern edge of the TP; in June, following the onset of the Asian summer monsoon, the strongest (severe) convection occurs in the southeastern part of the TP; and in July–August, strong southwesterly winds transport abundant moisture to the eastern and central areas of the TP, leading to formation of an active convection belt over southeastern TP. The results also show that in the western TP, the area with convection frequency greater than 6% occupies the southern plateau around 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 through the entire late summer with three major northward movements until reaching 34 N; and in the eastern TP, the convection is relatively active since the beginning of May and its northward stretching is slightly later than that over the central plateau. Overall, summer convective activities are unevenly distributed over the TP, with frequency of convection decreasing from south to north; and they also exhibit considerable intraseasonal variability, the maximum of which is found over the middle reach of the Yarlung Zangbo River and the southeastern plateau. EOF analysis of summer convection frequency over the TP reveals two leading modes, with the first mode being a dipole variation pattern between the Indian monsoon region and the southeastern TP, and the second mode a tripole pattern over the western TP, the Indian continent west of 80 E, and the South Asian continent east of 80 E.