南半球における最近の気候変動の解釈
David W J Thompson1, Susan Solomon
1Department of Atmospheric Science, Foothills Campus, Colorado State University, Fort Collins, CO 80523, USA. davet@atmos.colostate.edu
Science (New York, N.Y.)
|May 4, 2002
まとめ
南半球の気候の変動は,南半球の環状モードによって引き起こされます. 最近の傾向は,より強い極地渦が,オゾン層の枯渇に関連して,地域の気温に影響を与えていることを示しています.
科学分野:
- 大気科学 大気科学
- 気候のダイナミクス
- オゾン化学 オゾン化学
背景:
- 南半球 (SH) の気候の変動は,主に,大気循環の変化のパターンであるSH環状モードの影響を受けます.
- このモードは,SH環極渦の強さの変動によって特徴付けられます.
研究 の 目的:
- SHトロポスフィアの循環における最近の動向を解釈する.
- これらの傾向を,下層平流圏の極地渦の変化とオゾン層の減少と関連付ける.
- SHにおける観測された地域的な温度変化を説明する.
主な方法:
- SHにおける大気循環パターンの分析.
- SH環状モードと極性渦の強さの動向の調査.
- 循環傾向と光化学的なオゾン損失と地域的な気温データとの相関.
主要な成果:
- 最近のSHトロポスフィアの循環傾向は,より強い極性渦によって特徴づけられるSH環状モードの高インデックス状態へのバイアスを示しています.
- これらの循環傾向は,主に光化学的なオゾン層の枯渇によって引き起こされる,下層平流圏の極地渦中の最近の変化と強く関連しています.
- 強化された環極流は,南極半島とパタゴニアの温暖化,南極東部と南極高原の夏と秋の冷却に大きく貢献しています.
結論:
- 光化学的なオゾン損失は,極地渦に及ぼす影響を通じて,最近のSH気候動向の主要な原動力である.
- オゾン層の枯渇の影響を受けたSH環状モードの高指数バイアスは,南半球の高緯度の地域的な気温変化を大きく説明する.
- これらの関連性を理解することは,この地域の将来の気候変動の変動と影響を予測するために極めて重要です.
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