October 17th, Dr. Omid Alizadeh-choobari made an academic report entitled “Frequency of extreme El Ni？o and La Ni？a events under global warming”.

　　Dr. Omid Alizadeh-choobari is an Associate Professor in the Institute of Geophysics, University of Tehran, Iran. After graduating in Meteorology from the University of Tehran, Dr. Omid Alizadeh-choobari received his Ph.D. in Environmental Science from the University of Canterbury, New Zealand in 2013. Following his PhD, he moved to Florida to undertake a postdoctoral in Atmospheric Science at the Florida International University in 2014. His research interests include, extreme weather events, impacts of large-scale teleconnections on climate variability, dynamical downscaling and spatial and temporal variations in dust events. In July 2019, Dr. Omid Alizadeh-choobari invited in the 18th CTWF International Symposium on Aerosol and Climate Change, hosted by ICCES. He gave presentation on "Spatial and temporal variations of dust events over Iran".

　　The report was hosted by Professor Zhaohui Lin, Director of ICCES. The report clarified that under global warming the eastern equatorial Pacific warms faster than the surrounding ocean waters, which is accompanied with an increase of rainfall in the eastern equatorial Pacific. Thus, changes in the mean state of the tropical Pacific climate will be like an El Ni？o pattern under global warming. By applying the Oceanic Ni？o Index (ONI), it is found that the number of very strong El Ni？o events slightly increases under global warming and the rate of increase in the number of extreme La Ni？a events is greater than that of extreme El Ni？o events. Applying the modified Cai index shows a slight decrease of extreme El Ni？o events and a slight increase of extreme La Ni？a events under global warming. Thus, results of several previous studies which concluded that the number of extreme El Ni？o events nearly doubles under global warming are not supported by results of this study.

　　After the report was completed, the discussion session was set up. Dr. Omid Alizadeh-choobari actively interacted with the researchers and students present, and the atmosphere was lively.

　　10月17日，伊朗德黑兰大学副教授Omid Alizadeh-Choobari博士作了题为“全球变暖下极端厄尔尼诺和拉尼娜事件的发生频率”的学术报告。

　　Omid Alizadeh-Choobari博士是伊朗德黑兰大学地球物理研究所的副教授。Omid Alizadeh-choobari博士有着德黑兰大学授予的气象学博士学位，及新西兰坎特伯雷大学环境科学博士学位。在获得博士学位后，他于2014年移居佛罗里达，在佛罗里达国际大学进行大气科学领域的博士后研究。他的研究兴趣包括极端天气事件，大尺度遥相关对气候变率的影响，沙尘事件动态降尺度及其时空变率等。 2019年7月，Omid Alizadeh-Choobari博士应邀参加了由我中心主办的第18届CTWF国际气溶胶与气候变化国际研讨会，并应邀作了关于“伊朗上空沙尘事件的时空变率”的演讲。

　　此次学术报告由中心主任林朝晖研究员主持。报告提到，在全球变暖的情况下，赤道东太平洋的变暖速度快于周围的海水，伴随而来的是赤道东太平洋的降雨增加。因此，在全球变暖下，热带太平洋气候平均状态的变化将类似厄尔尼诺现象。通过应用海洋Ni？o指数(ONI)，科学家发现了在全球变暖下非常强烈的厄尔尼诺事件的数量略有增加，极端拉尼娜事件的数量增加率大于厄尔尼诺极端事件的数量。应用修正的Cai指数显示，在全球变暖下，极端厄尔尼诺事件略有减少，而极端厄尔尼诺事件则略有增加。因此，先前研究得出的全球变暖下的极端厄尔尼诺现象的数量几乎翻了一番的结论与这项研究的结果相悖。

　　Omid Alizadeh-Choobari博士完成报告后，还与在场的研究人员和学生进行了积极的互动，气氛十分热烈。