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地球生命圏研究機構

SELIS セミナー

日時

2009年12月1日(火) 17:00~

場所

地球水循環研究センター 3階・大講義室     

講演者

真鍋淑郎(プリンストン大学上席気象研究員、名大特別招聘教授)

「Simulation of Younger Dryas Event and Its Implication for Future Climate Change」

講演内容

Using a coupled ocean-atmosphere model, this study explores the physical mechanism responsible for so-called abrupt climate change such as Younger Dryas event. In response to massive fresh water discharge into northern North Atlantic over 500 years, the simulated thermohaline circulation (THC) weakens in the Atlantic Ocean, reducing surface temperature over the northern North Atlantic and surrounding regions. Upon the termination of fresh water discharge on the 500th year, the THC begins to intensify, regaining its original intensity in a few hundred years. The sudden onset and termination of fresh water discharge induce an irregular, multi-decadal fluctuation in the intensity of THC, yielding almost abrupt climate changes.

 A similar, but much weaker fluctuation of THC is also evident in the control integration of the coupled model without freshwater forcing. It is often accompanied by the multi-decadal fluctuation of the subarctic gyre, which yields surface salinity anomaly similar to “Great Salinity Anomaly”.

     

Finally, the role of THC in future climate change is discussed.