初夏孟加拉湾东部降水异常对印度洋海温偶极子的触发作用
投稿时间: 2016-05-03  最后修改时间: 2016-06-01  点此下载全文
引用本文:
摘要点击次数: 415
全文下载次数: 
作者单位E-mail
桂发银 中国人民解放军理工大学气象海洋学院 guifayin@163.com 
谭言科 中国人民解放军理工大学气象海洋学院 yktan@sohu.com 
李崇银 解放军理工大学 气象海洋学院LASG 中国科学院大气物理研究所  
黎鑫 解放军理工大学 气象海洋学院  
陈雄 解放军理工大学 气象海洋学院  
基金项目:国家自然科学基金项目(41490642);;国家重点基础研究发展计划(2013CB956200, 2015CB453200)
中文摘要:基于1982-2013年逐月NCEP资料及GODAS资料,采用回归分析、合成分析以及2.5层简化海洋模式数值模拟等方法,研究了热带东印度洋的大气和海洋过程对印度洋海温偶极子(Indian Ocean Dipole,IOD)东极(IOD east pole,IODE)海温异常的影响。结果表明,IODE海温异常的演变超前IOD西极(IOD west pole,IODW)海温异常的演变,并对IOD事件的生成和发展起到关键作用。初夏,来自阿拉伯海、中南半岛地区以及孟加拉湾西南部的水汽输送,导致孟加拉湾东部出现强降水。降水释放的潜热在热带东印度形成了一个跨越赤道的经向环流,有利于加强赤道东印度洋的过赤道气流,并在苏门答腊沿岸形成偏南风异常。该异常偏南风通过影响混合层垂向夹卷混合过程和纬向平流过程,导致IODE海温迅速下降。随后赤道东南印度洋异常东南风迅速增强以及赤道中印度洋东风异常的出现,增强了自东南印度洋向西印度洋的水汽输送,削弱了向孟加拉湾的水汽输送,使西南印度洋的降水增强,孟加拉湾东部的降水减弱。因此,IOD达到盛期前孟加拉湾东部的降水通过局地经向环流在苏门答腊沿岸形成偏南风异常,导致苏门答腊沿岸迅速的降温,并最终导致IOD事件的发生。
中文关键词:关键字:孟加拉湾东部降水  印度洋偶极子  东极降温  2.5层简化海洋模型
 
Possible Trigger of Early Summer Rainfall Anomalies over the Eastern Bay of Bengal on the Indian Ocean Dipole
Abstract:We explored the influence of atmospheric and oceanic processes on the sea surface temperature anomaly (SSTA) over the equator southeast Indian Ocean using regression analysis, composite analysis and a 2½-layer dynamic upper-ocean model based on the NCEP, GODAS reanalysis monthly data in the period 1982-2013. Results show that SSTA over the equator southeast Indian Ocean, which plays a key role in the formation and maintenance of Indian Ocean Dipole (IOD) event, has an advanced phase in comparison with that of the SSTA over the West Indian Ocean. Strong moisture transport from the Arabian Sea, northeastern Indo-China Peninsula, and southwest BOB to the eastern BOB results in significantly increased rainfall over the eastern BOB in early summer. Latent heating release because of the heavy rainfall anomaly over the eastern Bay of Bengal strengthens the local meridional circulation crossing the equator eastern Indian Ocean which can contribute to the southerly wind anomalies off the coast of Sumatra. The southerly wind anomalies off the coast of Sumatra which leads to a negative SSTA over the equator southeast Indian Ocean through enhanced entrainment and zonal advection. The southeast wind anomalies off the coast of Sumatra and easterly wind anomalies in the Middle East equatorial Indian Ocean stimulated by the negative SSTA over the equator southeast Indian Ocean contributes to the birth of the IOD event and the transportation of moisture from the equator southeast Indian Ocean to the west Indian Ocean, leading to less rainfall over the Bay of Bengal, equatorial southeast Indian Ocean and more over the west Indian Ocean.
keywords:Heavy rainfall anomaly over the eastern Bay of Bengal, Indian Ocean dipole, SSTA cooling over the IOD east pole, 2.5 layer dynamic upper-ocean model
查看全文  查看/发表评论  下载PDF阅读器