地球惑星科学専攻 地球科学輻合部特別講演会

日時: 2009年11月4日(水) 16:30 - 18:00
場所: 京都大学理学部6号館 201号室
題目: Simulation of Younger Dryas Event and Its Iimplication for Future Climate Change
講演者: 真鍋淑郎 先生 (プリンストン大学)

講演要旨:
Using a coupled ocean-atmosphere model, this study explores
the physical mechanism responsible for so-called abrupt
climate change such as Younger Dryas events. 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 induce an irregular, multi-decadal
fluctuation in the THC intensity, yielding almost abrupt
climate changes.

A similar, but much weaker fluctuation of the 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 the THC in future climate change is discussed.

問い合わせ先: 渡邊裕美子