南太平洋の熱帯水域の範囲の10年間の変動は,ヤング・ドライアスのイベント中に発生した
Thierry Corrège1, Michael K Gagan, J Warren Beck
1UR 055 Paléotropique, Institut de recherche pour le Développement, BP A5, Nouméa, New Caledonia. thierry.correge@noumea.ird.nc
Nature
|May 1, 2004
まとめ
1万2000年前のヤング・ドライアス期は,太平洋の熱帯地域を著しく冷却した. バヌアトゥの海面温度は4.5°C低下し,熱帯水循環の変化を示した.
科学分野:
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 海洋学 海洋学 海洋学
- 海洋地質学 海洋地質学
背景:
- 若年ドラヤス期 (約1万年) 12,000年前) は北半球の大幅な冷却を引き起こした.
- 南部中緯度および熱帯における気候の影響は,限られたデータがあるため,依然として十分に理解されていない.
- 過去の気候変化を理解することは,将来の気候変動を予測する上で極めて重要です.
研究 の 目的:
- 若干乾期における西南熱帯太平洋における海面温度 (SST) を再構築する.
- この期間の気候変動の空間的範囲とメカニズムを調査する.
- 熱帯水循環と降雨パターンの変化を分析する.
主な方法:
- 化石の巨大サンゴ (Diploastrea heliopora) の高解像度地化学分析 (Sr/Ca,18O/16O) を実施しました.
- サンゴは,ヴァヌアトゥの上昇したサンゴ礁のテラスで in situ で保存されました.
- 過去の海洋状態を再構築するために,骨格の記録を活用する.
主要な成果:
- バヌアトゥは,現代と比較して,若いドライアス時代に平均4.5±1.3°CのSST減少を経験しました.
- 年間SSTサイクルは増幅され,赤道に向かって熱帯水域の圧縮を示唆しました.
- 酸素同位体とSSTの正の相関は,南太平洋コンバージェンスゾーンが不活性であったことを示している.
結論:
- ユング・ドライアスは,南西の熱帯太平洋で著しい冷却をもたらした.
- 水質の圧縮を含む海洋学的変化は,この冷却の主要な原動力でした.
- 珊瑚からの古気候記録は,過去の気候の動態と循環パターンの重要な洞察を提供します.
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