Japan Geoscience Union Meeting 2018

Presentation information

[EJ] Poster

A (Atmospheric and Hydrospheric Sciences) » A-CG Complex & General

[A-CG38] Science in the Arctic Region

Thu. May 24, 2018 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Shun Tsutaki(The University of Tokyo), NAOYA KANNA(Arctic Research Center, Hokkaido University), Shunsuke Tei(北海道大学 北極域研究センター, 共同), Tetsu Nakamura(Faculty of Environmental Earth Science, Hokkaido University)

[ACG38-P03] On the atmospheric response experiment to a Blue Arctic Ocean

*Tetsu Nakamura1, Koji Yamazaki1, Meiji Honda2, Jinro Ukita2, Ralf Jaiser3, Doerthe Handorf3, Klaus Dethloff3 (1.Faculty of Environmental Earth Science, Hokkaido University, 2.Department of Environmental Science, Faculty of Science, Niigata University, 3.Alfred-Wegener-Institut)

Keywords:Arctic sea ice decline, Arctic Oscillation, Climate change, Extreme climate, Arctic amplification

We demonstrated atmospheric responses to a reduction in Arctic sea ice via simulations in which Arctic sea ice decreased stepwise from the present-day range to an ice-free range. In all cases, the tropospheric response exhibited a negative Arctic Oscillation (AO)-like pattern. An intensification of the climatological planetary-scale wave due to the present-day sea ice reduction on the Atlantic side of the Arctic Ocean induced stratospheric polar vortex weakening and the subsequent negative AO. Conversely, strong Arctic warming due to ice-free conditions across the entire Arctic Ocean induced a weakening of the tropospheric westerlies corresponding to a negative AO without troposphere-stratosphere coupling, for which the planetary-scale wave response to a surface heat source extending to the Pacific side of the Arctic Ocean was responsible. Because the resultant negative AO-like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification.