[M-IS08] 南大洋・南極氷床が駆動する全球気候変動

[MIS08-01] 過去5000年間の南極ドームふじ周辺の涵養量

★招待講演

*大藪 幾美¹、川村 賢二^1,2,3、藤田 秀二^1,2、井上 崚²、本山 秀明^1,2、福井 幸太郎⁴、平林 幹啓¹、保科 優⁵、栗田 直幸⁵、中澤 文男^1,2、大野 浩⁶、杉浦 幸之助⁷、鈴木 利孝⁸、津滝 俊^1,2、阿部 彩子⁹、庭野 匡思¹⁰、Parrenin Frédéric¹¹、齋藤 冬樹³、吉森 正和⁹ (1.情報・システム研究機構　国立極地研究所、2.総合研究大学院大学、3.海洋研究開発機構、4.立山カルデラ砂防博物館、5.名古屋大学、6.北見工業大学、7.富山大学、8.山形大学、9.東京大学大気海洋研究所、10.気象庁気象研究所、11.フランス環境地球科学研究所)

キーワード：涵養量、表面質量収支、南極、氷床、アイスコア 、完新世

We reconstructed surface mass balance (SMB) around Dome Fuji, Antarctica, over the last 5000 years using the data from 15 shallow ice cores and 7 snow pits. The depth-age relationships for the ice cores were determined by synchronizing them with a layer-counted ice core from West Antarctica (WAIS Divide ice core) using volcanic signals. The reconstructed SMB records for the last 4000 years show spatial patterns that may be affected by their locations relative to the ice divides around Dome Fuji, proximity to the ocean, and wind direction. The SMB records from the individual ice cores and snow pits were stacked to reconstruct the SMB history in the Dome Fuji area. The stacked record exhibits a long-term decreasing trend at -0.037±0.005 kg m^-2 per century over the last 5000 years in the preindustrial period. The decreasing trend may be the result of long-term surface cooling over East Antarctica and the Southern Ocean, and sea-ice expansion in the water vapor source areas. The multidecadal to centennial variations of the Dome Fuji SMB after detrending the record shows four distinct periods during the last millennium: mostly negative period before 1300 C.E., slightly positive for 1300–1450 C.E., slightly negative for 1450–1850 C.E. with a weak maximum around 1600 C.E., and strong increase after 1850 C.E. These variations are consistent with those of previously reconstructed SMB records in the East Antarctic plateau. The low accumulation rate periods tend to coincide with the combination of strong volcanic forcings and solar minima for the last 1000 years, but the correspondence is not clear for the older periods, possibly because of the lack of coincidence of volcanic and solar forcings, or the deterioration of the SMB record due to smaller number of stacked cores.