[A-CG24] 北極域の科学

[ACG24-P02] アラスカ沖バロー沿岸ポリニヤにおける海氷生産量の経年変動

*平野 大輔¹、深町 康²、渡邊 英嗣³、岩本 勉之⁴、大島 慶一郎²、田村 岳史¹ (1.国立極地研究所、2.北海道大学低温科学研究所、3.海洋研究開発機構、4.紋別市役所)

キーワード：ハイブリッド潜熱・顕熱ポリニヤ、海氷生産、経年変動

Recently, it has been proposed that the Barrow Coastal Polynya (BCP), previously considered to be a latent heat polynya, is a “wind-driven” hybrid latent/sensible heat polynya, with both features caused by the same northeasterly wind (Hirano et al., 2016). In this study, we examine the interannual variability of sea ice production in the BCP from 2002/03 to 2010/11 during AMSR-E operation period, with focus on the northeasterly wind that characterizes the BCP as a hybrid coastal polynya. Throughout the ice-growth season (November–May), sea ice production was the highest in 2003/04 and the lowest in 2010/11. In 2003/04, amount of the suppressed sea ice production was also highest, when ~30% of the BCP ice production was suppressed by the ocean heat transport associated with warm water upwelling. Wind pattern around the BCP region varies from year to year, and frequency and magnitude of the northeasterly wind correlate well with sea level pressure difference between the Beaufort High and Aleutian Low. Compared with climatology, the northeasterly wind in the BCP was more frequent and stronger in 2003/04 due to strengthening of the Beaufort High. In contrast, it was less frequent and weaker in 2010/11 due to weakening of both the Beaufort High and Aleutian Low. Frequency and magnitude of the northeasterly wind, mainly regulated by variabilities of the Beaufort High and Aleutian Low, are considered to be major factors of the interannual variability of sea ice production in the BCP.