2021/09/29 - 分享人:王旭栋 冯小芳
发布时间: 2021-09-26

题目:西北太平洋反气旋——夏季亚洲季风区季节内至年际尺度基本模态

报告人:王旭栋,复旦大学大气与海洋科学系博士后,合作导师张人禾教授。于2021年获得南京信息工程大学气象学博士学位,导师管兆勇教授和谢尚平教授。主要研究方向为海气相互作用、热带大气季节内振荡和季风动力学等。

摘要:亚洲夏季风跨时间尺度变率的特征及其气候影响一直是国内外相关领域研究的热点。本研究指出夏季西北太平洋反气旋是印太暖池区大气季节内至年际尺度跨尺度共有基本模态,受局地大气波流相互作用和对流反馈过程影响。年际尺度的西北太平洋反气旋与ENSO准两年周期存在密切联系;季节内尺度的西北太平洋反气旋符合MJO的“水汽模”理论,主要向北传播影响亚洲季风区气候变率。此外,本研究还从跨尺度基本模态角度出发,简单探讨了20162020年亚洲夏季风异常的特征和形成机理。


题目:A Multidecadal-Scale Global Teleconnection over the Past Millennium and Its Recent Impacts on Tropical Cyclone Activity

报告人:Dr. Xiaofang Feng is a postdoctoral scholar at the Department of Atmospheric and Oceanic Sciences and the Institute of Atmospheric Sciences, Fudan University. She holds a Ph.D. degree in Meteorology from Nanjing University of Information Science and Technology (NUIST), and has been as a Joint Ph.D. student at the Department of Geography, University of California, Santa Barbara (UCSB). She obtained a M.S. degree in Meteorology from NUIST, and a B.S. degree in Atmospheric Sciences from Guangdong Ocean University. Her research interests are in tropical cyclone dynamics, climate variability and change in Large-scale atmosphere/ocean systems, paleoclimate, future climate change, and coupled climate modeling.

摘要:In the past 40 years, the global annual mean surface temperature has experienced a nonuniform warming. It exhibits significant asymmetry between the Arctic and Antarctic, with intermittent and spatially varying warming trends along the Northern Hemisphere (NH) mid-latitudes and a slight cooling in the tropical eastern Pacific. Here, we show that these nonuniform features are likely tied together by tropical eastern Pacific sea surface temperatures (SSTs), via a global atmospheric teleconnection. This tropically driven teleconnection is associated with a Pacific SST pattern resembling the interdecadal Pacific oscillation (IPO), and hereafter referred to as the IPO-related bipolar teleconnection (IPO-BT). The IPO-BT mode can be consistently obtained as a leading circulation mode over the past 100, 400 and 2000 years, which may serve as an important internal mode that regulates climate variability on multi-decadal scales. The spatial nonuniformity of recent temperature trends may be partially explained by the enhanced appearance of the IPO-BT mode by a transition of the IPO toward a cooling phase in the eastern Pacific in the past decades. Further, this internal mode plays a role in the recent shift of the basin-wide mean location of tropical cyclone (TC) formation in the western North Pacific (WNP). The poleward shift of the mean latitude of TC formation is accompanied by westward retreat of the monsoon trough (MT) and westward extension of the tropical upper tropospheric trough (TUTT), which is closely associated with IPO-related SSTs. Thus, low-frequency SST variability in the tropical Pacific acts as an important internal dynamical source to jointly regulate recent climate variability along with anthropogenic forcing.