Vortex genesis over the Bay of Bengal in spring and its role in the onset of the Asian Summer Monsoon
Vortex genesis over the Bay of Bengal in spring and its role in the onset of the Asian Summer Monsoon
复制标题
春季孟加拉湾涡旋生成及其在亚洲夏季风爆发中的作用
DOI：
10.1007/s11430-010-4125-6
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Mao JiangYu
中科院分区：
文献类型：
--
作者：
Wu GuoXiong;Guan Yue;Wang TongMei;Liu YiMin;Yan JingHui;Mao JiangYu
利用多源数据集详细研究了与1998年亚洲夏季风爆发有关的物理过程。研究表明，春季北印度洋和热带亚洲地区强烈的海-气-陆相互作用是诱发孟加拉湾季风爆发涡旋（BOB）发生和发展的一个基本因素，而该涡旋又触发亚洲夏季风的爆发。在春季，印度和印度支那半岛强烈的地表感热被转移到大气中，形成突出的态势气旋环流，在阿拉伯海和BOB北部形成反气旋环流，那里的海洋接收到丰富的太阳辐射。北印度洋沿岸相应的表层风使海洋产生海流和上升流，导致海温（SST）冷却。4月下旬至5月上旬，随着中南半岛降水的增加，东BOB的近海流消失或发展为陆上流，导致海温升高。从阿拉伯海东南部到BOB东部，形成了一个海温> ~ 31℃的西南-东北向的春季BOB暖池。5月初，由于南北半球经向海温梯度和非洲地表感热，索马里横贯赤道气流形成。在沿赤道的惯性波动过程中，索马里气流与北阿拉伯海上空的反气旋在相位上重叠。反气旋东侧辐合的寒冷北风使惯性槽内的西风带迅速增加，海面向大气释放增强的感热。这种感热强迫的气旋涡度叠加在惯性槽上，使其涡度强度进一步增大。由于大气惯性运动被破坏，气流在一个增强的气旋曲率中偏离惯性轨迹，然后向北转向BOB北部的暖池。因此，它与BOB北部上空的反气旋南侧偏东气流汇合，在斯里兰卡以东形成一个气旋环流中心。与气旋环流同时存在的是由于温暖的海洋加热对流层低层而产生的大气势能。最终在斯里兰卡东部产生了BOB季风开始涡（MOV）。当MOV向北移动到暖池时，它迅速发展，使得纬向副热带高压在东副热带高压带上分裂。因此，MOV南侧和东侧的热带西风带与北侧的副热带西风带合并，导致BOB东部和印度支那半岛西部对流活跃，亚洲夏季风爆发。
Physical processes associated with onset of the 1998 Asian summer monsoon were examined in detail using multi-source datasets. We demonstrated that strong ocean-atmosphere-land interaction in the northern Indian Ocean and tropical Asian area during spring is a fundamental factor that induces the genesis and development of a monsoon onset vortex over the Bay of Bengal (BOB), with the vortex in turn triggering onset of the Asian summer monsoon. In spring, strong surface sensible heating over India and the Indochina Peninsula is transferred to the atmosphere, forming prominentin situcyclonic circulation, with anticyclonic circulations over the Arabian Sea and northern BOB where the ocean receives abundant solar radiation. The corresponding surface winds along the North Indian Ocean coastal areas cause the ocean to produce thein situoffshore currents and upwelling, resulting in sea surface temperature (SST) cooling. With precipitation on the Indochina Peninsula increasing from late April to early May, the offshore current disappears in the eastern BOB or develops into an onshore current, leading to SST increasing. A southwest-northeast oriented spring BOB warm pool with SST >31°C forms in a band from the southeastern Arabian Sea to the eastern BOB. In early May, the Somali cross-equatorial flow forms due to the meridional SST gradient between the two hemispheres, and surface sensible heat over the African land surface. The Somali flow overlaps in phase with the anticyclone over the northern Arabian Sea in the course of its inertial fluctuation along the equator. The convergent cold northerlies on the eastern side of the anticyclone cause the westerly in the inertial trough to increase rapidly, so that enhanced sensible heat is released from the sea surface into the atmosphere. The cyclonic vorticity forced by such sensible heating is superimposed on the inertial trough, leading to its further increase in vorticity strength. Since atmospheric inertial motion is destroyed, the flow deviates from the inertial track in an intensified cyclonic curvature, and then turns northward toward the warm pool in the northern BOB. It therefore converges with the easterly flow on the south side of the anticyclone over the northern BOB, forming a cyclonic circulation center east of Sri Lanka. Co-located with the cyclonic circulation is a generation of atmospheric potential energy, due to lower tropospheric heating by the warm ocean. Eventually the BOB monsoon onset vortex (MOV) is generated east of Sri Lanka. As the MOV migrates northward to the warm pool it develops quickly such that the zonal oriented subtropical high is split over the eastern BOB. Thus, the tropical southwesterly on the southern and eastern sides of the MOV merges into the subtropical westerly in the north, leading to active convection over the eastern BOB and western Indochina Peninsula and onset of the Asian summer monsoon.
登录
查看更多内容
DOI：
10.1002/qj.49711850705
发表时间：
1992-07-01
影响因子：
8.9
作者：
WEBSTER, PJ;YANG, S
通讯作者：
YANG, S
DOI：
--
发表时间：
1981-04
期刊：
--
影响因子：
--
作者：
木村 竜治
通讯作者：
木村 竜治
影响因子：
4.9
作者：
M. Ting;M. Hoerling;Taiyi Xu;Arun Kumar
通讯作者：
M. Ting;M. Hoerling;Taiyi Xu;Arun Kumar
影响因子：
5.2
作者：
W. M. Gray
通讯作者：
W. M. Gray
DOI：
10.3402/tellusa.v34i4.10822
发表时间：
1982-08
期刊：
Tellus A
影响因子：
--
作者：
M. Mak;C. Kao
通讯作者：
M. Mak;C. Kao