摘要
本研究的第Ｉ部分用资料分析证明，由于青藏高原的热力强迫和动力强迫，１９８９年亚洲季风首先在孟加拉湾（ＢＯＢ）东岸爆发，接着才有南海（ＳＣＳ）季风爆发和印度季风爆发。在亚洲季风爆发的这三个阶段中，每阶段都伴有高原上空气柱的急速升温。本文是第Ｉ部分的继续。它指出：高原上空气柱的每一次急速升温都与中高纬度源于地中海上空的、频率为２～３周的低频（ＴＴＯ）暖脊东传到高原上空相联系。季风爆发的每一阶段都伴有从南半球向北传播的、频率为３０～６０天的低频（ＭＪＯ）散度扰动和从热带西太平洋向西传播的、频率为２～３周的低频（ＴＴＯ）散度扰动。当这些低频扰动的暖位相和上升位相在所定义的“东亚季风区”（ＥＡＭＡ）锁相时，亚洲季风阶段性爆发出现。
In Part I of this study, analysed data were employed to prove that due to the thermal as well as mechanical forcings of the Tibetan Plateau, the 1989 Asian monsoon onset appeared firstly over the eastern coast of the Bay of Bengal (BOB), then the South China Sea (SCS) and Indian monsoon onsets followed consequently During each of these three stages of the Asian monsoon onset, the air temperature over the plateau region presents a rapid increase This part, the continuation of Part I, shows that each of these three rapid increases in temperature is associated with the arrival at the plateau region of the warm phase of the two- to three-week low frequency mode (TTO) of the upper tropospheric temperature originated from the Mediterranean Sea and propagating east-southeastwards Each of the onset stage is also accompanied by the arrival in the East Asian Monsoon Area (EAMA) of the rising phase of the 30～60 day northward propagating oscillation (MJO) of wind divergence from the Southern Hemisphere and of the westward propagating TTO of wind divergence from the western tropical Pacific It is therefore concluded that the phase locking of the warm or rising phases of there different types of low frequency oscillation in the EAMA is the determinant factor in controling the timing of Asian monsoon onset
出处
《大气科学》
CSCD
北大核心
1999年第1期51-61,共11页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金
国家科委攀登B项目
关键词
TTO
MJO
季风爆发
大气
热力作用
two- to three-week oscillation 30～60 day oscillation East Asian monsoon area phase locking
