継続的に超冷却された液体の水が -37.5°Cまで下がった深層のコンベクト雲
1Institute of Earth Sciences, the Hebrew University of Jerusalem, Israel. daniel@vms.huji.ac.il
Nature
|June 6, 2000
まとめ
雲の過程を理解する上で極めて重要な超冷却液体の水は,深層のコンベクティブ雲の中で発見されました. これらの発見は,液体の水が -37.5°Cまで持続し,天気と気候モデルに影響を与えることを示しています.
科学分野:
- 大気科学 大気科学
- クラウド物理学 クラウド物理
- 気象学 気象学 気象学
背景:
- 高度に超冷却された水 (0°C以下の液体水) は,シラス雲や波雲で知られているが,深層コンベクティブ雲では十分に研究されていない.
- 衛星データは,大陸のコンベクティブ・ストームで,非常に超冷却された水の頻繁な発生を示しています.
- 以前の研究では,深いコンベクティブ雲の頂上にある超冷却水に関する in situ 測定が欠けていました.
研究 の 目的:
- 深層コンベクティブ雲の極度に超冷却された水の in situ 測定を報告する.
- 非常に低い温度で液体の水の量と滴の大きさを定量化するために.
- クラウドプロセスのシミュレーションを改善し,気候の影響を理解するためのデータを提供します.
主な方法:
- 深層コンベクティブ雲の中で航空機の計測器を用いたインシットー測定.
- 濃縮水の含有量と,零下温度下でのドロップレットサイズ分布の分析.
- 凍結メカニズムを推論するために,液体から氷への相変化の観測.
主要な成果:
- 深層コンベクティブ雲の凝縮された水のほとんどは,-37.5°Cまで液体のままである.
- 液体の水の含有量は1.8gm−3に達し,以前報告された量よりも数桁高い.
- ドロップレットの中央体積直径は17マイクロメートルでした.
- 氷は,わずかに低い温度でのみ観察され,均質な凍結を示唆しました.
結論:
- 深いコンベクティブ雲には,かなりの量の超冷却された液体の水が含まれます.
- これらの発見は,混合段階のクラウドプロセスに関する既存の仮定に異議を唱えます.
- このデータは,数値的な天気予報と気候モデルの改善に不可欠であり,特に降雨,,電化に関するものです.
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