:::
105/11/22 14:00 中山大學海洋科學系曾若玄教授 演講
演講公告
張貼人：網站管理員 ╱ 公告日期：2016-11-16演 講 公 告
主講人：曾若玄 教授
地點：中央大學科學一館S-325教室
摘要：
講題：Mixed-layer current and cyclonic eddy induced by global tropical cyclones
主講人：曾若玄 教授
中山大學海洋科學系
時間：11月22日（星期二）下午2點
地點：中央大學科學一館S-325教室
摘要：
Global velocity data from drifters of the Surface Velocity Program and the sea surface height and geostrophic velocity data from satellite altimetry observations under tropical cyclones (TCs) were analyzed to demonstrate strong ocean currents and their characteristics under various storm intensities in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH). Mean TC's translation speed (Uh) is faster in the NH (~4.7 m s-1) than in the SH (~4.0 m s-1), owing to the fact that TCs are more intense in the NH than in the SH. The rightward (leftward) bias of ocean mixed-layer (OML) velocity occurs in the NH (SH). As a result of this slower Uh and thus a smaller Froude number in the SH, the flow patterns in the SH under the same intensity levels of TCs are more symmetric relative to the TC center and the OML velocities are stronger than those in the NH. Several special cases were reported in this study showing the occurrence of prominent cyclonic eddies with a life span of several months which were induced by slow-moving (Uh ~ 1 m s-1) and intense (category 3, 4, and 5 of the Saffir-Simpson Scale) TCs, both in the NH and SH. This study provides the first characterization of the near-surface OML velocity response to all recorded TCs in the SH from direct velocity measurements. Our findings provide observational evidence of generation of extremely strong cyclonic oceanic eddy or enhancement of weak existing cyclonic oceanic eddy under slow-moving category-5 TCs, which will support further improvements of their representation in ocean dynamics and numerical air-ocean prediction.
最後修改時間：2016-11-17 AM 8:53
