高解像度の地下水氷の分布は,火星で
1School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287-6305, USA. joshband@asu.edu
Nature
|May 4, 2007
まとめ
水氷は火星の浅い地表で安定しており,その深さは緯度によって異なります. 新しい熱画像は局所的な変化を明らかにし,活発な火星の水循環と氷床の深さに影響を与える要因を示唆しています.
科学分野:
- 惑星科学は惑星科学である.
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 理論的なモデルは,火星の浅い地下 (<1-2m) で高緯度で安定した水氷を予測しています.
- ガンマ線スペクトロメーター (GRS) の以前の水素検出は,緯度が下がるにつれて氷床の深さが増加するモデルをサポートしました.
- 過去の測定は,GRSの足跡によって制限され,氷の分布の詳細な観察を妨げました.
研究 の 目的:
- 火星の地下水の氷の分布におけるサブキロメートルのスケールの異質性を調査する.
- 地元の地表の特徴と熱的性質が氷床の深さに及ぼす影響を分析する.
- 火星の現在の水循環と気候の動態への影響を評価する.
主な方法:
- 火星オデッセイの熱放出画像システム (THEMIS) を利用して,季節的な地表温度反応を観察しました.
- 熱データを分析して,地表の性質と水氷の分布をサブキロメートルのスケールで推測しました.
- 観測データを,水氷の安定性と大気の交換の理論モデルと比較した.
主要な成果:
- 水氷の深さを影響する表面の異質性をサブキロメートルのスケールで観測する能力を実証した.
- いくつかの大気モデルと一致する,水の氷の深さの重要な地域的および局所的な変動を明らかにしました.
- 理論的な安定性からの偏差がある地域を特定し,氷床の厚さに影響を与える追加の要因を示した.
結論:
- 火星の地下水の氷の分布は,局所的なスケールでは非常に変動します.
- 観測は,軌道上の気候サイクルに反応する活発な火星の水循環を支持しています.
- 理論的な氷の安定性深度からの偏差を引き起こす要因を理解するためにさらなる研究が必要です.
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