报告题目: Reexamination of the moisture-vortex and baroclinic instabilities in the South Asian monsoon
报告人: 李天明 教授 （美国夏威夷大学）
时间: 2024年3月27日，周三下午15:00-16:30
地点:大气楼 D103报告厅
Observational analyses reveal that a dominant mode in the South Asian Monsoon region in boreal summer is westward-propagating synoptic-scale disturbances with a typical wavelength of 4000 km that are coupled with moistening and precipitation processes. The disturbances exhibit an eastward tilt during their development before reaching their maximum activity center. A 2.5-layer model that extends a classic 2-level quasi-geostrophic model by including a prognostic lower-tropospheric moisture tendency equation and an interactive planetary boundary layer was constructed. The eigenvalue analysis of this model shows that the most unstable mode has a preferred zonal wavelength of 4000 km, a westward phase speed of 6 m s-1, an eastward tilt vertical structure and a westward shift of maximum moisture/precipitation centers relative to the lower-tropospheric vorticity center, all of which agree with the observations. Sensitivity experiments show that the moisture-vortex instability determines, to a large extent, the growth rate, while the baroclinic instability helps set up the preferred zonal scale. The current work sheds light on understanding the moisture-vortex and the baroclinic instability in a monsoonal environment with a pronounced easterly vertical shear.
个人简介 ：
李天明教授，美国夏威夷大学终身教授。担任世界气象组织（WMO）世界天气研究计划（WWRP）季风工作组成员、气候变化与可预报性（CLIVAR）/大气环流模式比较计划（AMIP）东亚气候工作组成员、亚太经济合作组织韩国釜山气候中心（APCC）科学家咨询组成员，《Journal of Climate》、《Earth Science Reviews》、《Bulletin of the American Meteorological Society》的责任编辑和《Journal of Meteorological Research》副主编。获夏威夷大学杰出研究金奖。从事热带气象学、季风、台风以及气候动力学等方面的研究。发表论文400 余篇，Google Scholar 引用20000 余次，H-index: 80。
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