大気と地球の表面の上部で発生する熱帯性エアロゾール圧力の大きな違い
1Center for Clouds, Chemistry, and Climate, Scripps Institution of Oceanography, University of California at San Diego, La Jolla 92093, USA.
Nature
|May 16, 2000
まとめ
人為的なエアロゾールは,気候予測に大きく影響を与えます. この研究は,熱帯のエアロゾール強制を定量化し,表面と大気の上部の太陽放射線加熱の間の3倍の差を明らかにし,水循環に潜在的な影響を示唆しています.
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:
- 人為的なエアロゾールは,気候変動の予測における大きな不確実性を表しています.
- 特に熱帯では,エアロゾールの放射性強制を直接観測することは極めて重要ですが,限られています.
- 南アジア大陸から発生する熱帯性エアロゾールは,ほとんど理解されていません.
研究 の 目的:
- 高精度 (+/- 5%) のエアロゾールの放射性強制を定量化するための観測方法を開発し,提示する.
- 地球の表面と大気圏の上部のエアロゾール強制を同時に測定するために.
- インド洋上空における太陽の放射性加熱に対する熱帯性エアロゾールの影響を調査する.
主な方法:
- カリブレーションされた衛星放射線測定を用いた.
- 地上での検証のために5つの独立した表面放射測定器を使用した.
- 冬季 (1998年-1999年) のインド洋の熱帯北部の晴れた空の太陽放射熱の量化.
主要な成果:
- 海洋表面での太陽放射熱の有意な減少が観察されました (12-30 Wm(-2)).
- 大気圏の上部 (4-10 Wm(-2)) の太陽放射熱のより小さな減少を測定しました.
- 表面と大気上の強制力の3倍の差を特定し,主に灰塵の吸収に起因する.
結論:
- この研究は,エアロゾールフォッシングを定量化するための正確な方法を示しています.
- 観測された大きな表面強制力と,表面強制とTOA強制力の差は,熱帯のエアロソルが水循環を減速させることを示唆しています.
- 発見は,地域的およびグローバルな気候の動態における熱帯的な人為的なエアロゾールの重要な役割を強調しています.
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