タイタンの極循環の逆転による上層大気中の活性化学と動力学

Nicholas A Teanby¹, Patrick G J Irwin, Conor A Nixon

¹School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK. n.teanby@bristol.ac.uk

Nature

|November 30, 2012

まとめ

タイタンの中間大気循環は,これまで考えられていたよりも高く,少なくとも600キロメートルに達しています. この発見は,土星の最大の衛星の霧形成と大気化学の理解に影響を与えます.

科学分野:

惑星科学は惑星科学である.
大気科学大気科学
アストロケミストリーアストロケミストリー

背景:

タイタンは,地球のような圧力の濃い窒素大気を持っています.
現在の数値モデルでは,タイタンの熱帯圏を正確にシミュレートしていますが,大気中部の条件に苦労しています.
メインのハズデッキの上には"分離したハズ"と呼ばれる独特のハズ層が観測されています.

研究の目的:

タイタンの中間大気循環の上限を調査するために.
タイタンの大気循環の要因と影響を理解するためです.
観測された"分離した霧"層の説明を再評価する.

主な方法:

タイタンの南極上の微量ガス蓄積の分析 2009年の赤道後の循環の逆転に続いて.
観測データと大気循環モデルの比較.
霧と微量ガスに対する太陽熱と赤外線冷却効果の評価.

主要な成果:

南極上では,微量ガスが大量に蓄積されていることが観測されました.
証拠によると,大気中部の循環は少なくとも600キロメートルに及ぶという.
霧による太陽熱と赤外線冷却は,熱圏に広がる重要な要因である.

結論:

タイタンの中間大気循環は,以前にモデル化されたものよりも広範囲に及ぶ.
霧による加熱と冷却は,上層大気の重要な要因です.
"分離したハズ"は,ハズ粒子の構造の変化によるものかもしれない.

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