2026-02-03 東京大学,東北大学
火星における静音時(左)と砂嵐時（右）の比較
静音時は大気温度が低く雲になりやすいため、上空まで水蒸気が到達しない一方、砂嵐時は大気温度が上昇し雲を押し上げ、水が宇宙空間へ消失する。
＜関連情報＞
- https://www.k.u-tokyo.ac.jp/information/category/press/0029105.html
- https://www.k.u-tokyo.ac.jp/assets/files/火星で起きた「季節外れ」の水消失_WEB.pdf
- https://www.nature.com/articles/s43247-025-03157-5
火星北部の夏に、局所的な強い砂嵐によって引き起こされた季節外れの水の流出 Out-of-season water escape during Mars’ northern summer triggered by a strong localized dust storm
Adrián Brines,Shohei Aoki,Frank Daerden,Michael S. Chaffin,Samuel A. Atwood,Susarla Raghuram,Bruce A. Cantor,Yannick Willame,Loïc Trompet,Geronimo L. Villanueva,Michael J. Wolff,Michael D. Smith,Christopher S. Edwards,Ian R. Thomas,Giuliano Liuzzi,Lori Neary,Manish R. Patel,Miguel Angel López-Valverde,Armin Kleinböhl,Hoor AlMazmi,James Whiteway,AnnCarine Vandaele,Bojan Ristic & Giancarlo Bellucci
Communications Earth & Environment Published:02 February 2026
DOI:https://doi.org/10.1038/s43247-025-03157-5
Abstract
Mars almost certainly had a considerable amount of water in its past. Recent observations reveal that during southern summer, when the atmosphere is warmer and dustier, water vapor can reach high altitudes without condensing, leading to water loss to space. Here, by combining infrared, visible, and ultraviolet data from multiple Mars orbiters, we identify a new pathway for water loss, observed for the first time to our knowledge during the opposite season. Our findings show that a strong, localized, and short-lived dust storm in Martian Year 37 (August 2023) drove considerable vertical transport of water vapor in the northern summer season. Just days after the storm, enhanced water vapor concentrations were observed at altitudes over 40 km across northern high latitudes, followed by an increase in escaping hydrogen detected at the exobase. These results suggest that water loss on Mars can be triggered by strong local dust storms at any time of year.
