北半球における最近の熱帯の拡大は,主に黒炭素と熱帯オゾンによって引き起こされている

Robert J Allen¹, Steven C Sherwood, Joel R Norris

¹Department of Earth Sciences, University of California, Riverside 92521, USA. rjallen@ucr.edu

Nature

|May 19, 2012

まとめ

ブラックカーボンと熱帯オゾンエアロゾールは,温室効果ガスとは異なり,北半球の熱帯拡大の主な原動力です. これらの温暖化剤は,大気循環をシフトさせ,気候ゾーンを移転させます.

科学分野:

大気科学大気科学
気候科学気候科学
環境科学環境科学

背景:

観測研究は,地球温暖化と相関する熱帯帯の拡大を示しています.
熱帯の膨張は,大気循環と気候圏のシフトに影響を与えます.
南半球の膨張はオゾン層の枯渇と関連しているが,北半球の要因は模範では不明で再現されていない.

研究の目的:

北半球の熱帯帯の拡大の要因を調査する.
熱帯の膨張におけるエアロゾールと温室効果ガスの役割を決定する.
熱帯の拡大における観測された夏の最大値を説明するために.

主な方法:

詳細なエアロゾール物理学の気候モデルを使用しました.
温室効果ガス,ブラック・カーボン・エアロゾール,大気圏オゾンの影響をシミュレートした.
大気温上昇が中緯度と熱帯圏のジェットに与える影響を分析した.

主要な成果:

ブラック・カーボンと熱帯オゾン・エアロゾールの増加は,温室効果ガスよりも熱帯の膨張を推進する上でより効果的であった.
これらのエアロゾールは,熱帯の拡大における観測された夏の最大値を説明できる.
中緯度のエアロゾールによる大気の加熱は,熱帯圏ジェットの極方向のシフトを引き起こした.

結論:

ブラックカーボンとトロポスフィアのオゾンは,北半球の熱帯の拡大の最も可能性が高い原因です.
人間の活動は,これらのエアロゾール剤に大きく影響を与えます.
モデルの無感性を調査し,エアロゾールフォッシングの推定値を精査するためにさらなる研究が必要です.

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