[A-CG24] 北極域の科学

[ACG24-P01] 気候モデルMIROCを用いた北極海における海氷変動のメカニズムと予測可能性

*小野 純¹、建部 洋晶¹、小室 芳樹¹、野津 雅人²、石井 正好² (1.海洋研究開発機構、2.気象庁気象研究所)

キーワード：北極、海氷、気候モデル

The Arctic environment has markedly changed due to the rapid decline of sea ice in summer Arctic Ocean. The retreat of sea-ice cover could be associated with the Arctic amplification and an increase in the frequency of severe cold winters in the Northern Hemisphere mid-latitudes. Accurate predictions of sea-ice variability on seasonal to decadal time-scales and its mechanisms would be useful for further progress in science as well as socio-economic activity. To examine the mechanisms and predictability for Arctic sea-ice variability, we analyze the control simulations from the Arctic Predictability and Prediction On Seasonal to Inter-annual Timescales (APPOSITE) project. The model used for the APPOSITE is the climate model MIROC 5.2 in which external forcing is fixed in 2005. The time evolution in sea-ice extent and volume shows that an extreme reduction event occurs one or two for a century even without the global warming trend. The spatial feature in sea-ice distribution and its reduction mechanisms resemble those in 2007. This suggests that an anomalous sea-ice loss could be caused by only natural variability. We have currently investigated the key factors closely related to the sea-ice variability.