报告题目：A Theory for Seasonal Predictability Barrier

报告人：刘征宇 教授（俄亥俄州立大学）

报告人简介：

刘征宇，1982年毕业于南京气象学院获学士学位，1985年获中国科学院大气物理研究所硕士学位，1991年获美国麻省理工学院和Woods Hole海洋研究所联合博士学位。现任美国俄亥俄州立大学地理系气候动力学Thomas教授，主要从事海-地-气系统相互作用与气候动力学、大洋环流动力学、古气候模拟及地球系统模拟等方面的研究，其领衔的研究团队多次在Science、Nature、PNAS等顶级学术刊物上发表研究成果。Google Scholar Citation显示(截止到2021年1月14日)，刘征宇教授有超过17000次引，h指数为68, i10指数为249。刘征宇教授同时是美国科学促进会(AAAS)会士、美国气象学会(AMS)会士和美国地球物理学会(AGU)会士。他曾长期担任威斯康辛大学麦迪逊分校气候研究中心主任职务，担任美国国家科学基金(NSF)古时研究组成员、CCSM古气候模拟工作组联合主席、气候变率与可预测性计划(CLIVAR)科学指导委员会成员等学术团体职务。

Abstract

A theory is developed in stochastic climate models for understanding the general features of seasonal predictability barrier (PB), which is characterized by a band of maximum decline in autocorrelation function phase-locked to a particular season. The theory is first developed in the damped persistence model. Our theory determines the forcing threshold, timing and intensity of the seasonal PB as a function of the damping rate and seasonal forcing. A seasonal PB is found to be an intrinsic feature of a stochastic climate system forced by either seasonal growth rate or seasonal noise forcing. A PB is generated when the seasonal forcing, relative to the damping rate, exceeds a modest threshold. Once generated, all the PBs occur on the same calendar month, forming a seasonal PB. The PB season is determined by the decline of the seasonal forcing as well as the delayed response associated with damping. The intensity of the PB is determined mainly by the amplitude of the seasonal forcing. The theory is able to explain the general features of the seasonal PB of the observed SST variability over the world. The PB theory is further developed in a recharge oscillator model with the application to ENSO seasonal PB in both SST and heat content. Our theory provides a general framework for the understanding of the seasonal PB of climate variability.

时间：2021年04月30日（周五）21:00-23:00

报告方式：腾讯会议，会议号：790 531 659

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