過去40年間における海面上昇は,衛星観測と現地観測によって決定される
C Cabanes1, A Cazenave, C Le Provost
1Laboratoire d'Etudes en Géophysique et Océanographic Spatiales, Centre Nationale d'Etudes Spatiales, 18 Avenue Edouard Belin, Toulouse 31400, France.
Science (New York, N.Y.)
|October 27, 2001
まとめ
世界の平均海面上昇は,主に海洋熱膨張によるものです. 潮測定器のデータは,熱気学的な海面測定におけるサンプリングバイアスのために,20世紀の海面上昇を過大評価している可能性があります.
科学分野:
- 海洋学 海洋学とは
- 気候科学 気候科学
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 世界平均海面上昇 (SLR) は,気候変動の重要な指標である.
- 衛星高度計 (例えば,トペックス/ポセイドン) は,SLRの世界的な測定を提供します.
- 潮位計は,長期的かつ局所的な海面記録を提供します.
研究 の 目的:
- 衛星で観測されたSLRを海洋学データと調和させるため.
- 潮位計から過去のSLRの推定値の潜在的なバイアスを調査する.
- 観測された海面の変化に対する熱膨張の寄与を評価する.
主な方法:
- トペックス/ポセイドン衛星の高度測定データ (1993-1998) の分析
- 潮位計の記録と計算された熱気学的な海面の変化 (1955-1996) の比較.
- 熱気学的な海平面計算に対する空間サンプリング効果の評価.
主要な成果:
- 観測された世界平均SLR 3.2 ± 0.2 mm/年 (1993-1998) は,海洋熱膨張によって完全に説明されます.
- 潮位計のデータと,現地サイトでの計算された熱膨張 (1955-1996) の間の良好な一致.
- サーモステリックSLRは,潮位計の場所でのサブサンプリング時に世界の平均の2倍であることが判明しました.
結論:
- 海洋熱膨張は,最近の世界の平均海面上昇の主な要因である.
- 潮位計のデータは,空間的なサンプリングを適切に考慮しない場合,過去のSLRの過大評価につながる可能性があります.
- 20世紀のSLRの推定値を修正された方法論を使用して再検討することをお勧めします.
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