Nature Communications Earth & Environment (2026) https://doi.org/10.1038/s43247-025-03157-5
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 Bellucc
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.
Vertical distribution of water vapor volume mixing ratio (VMR) as a function of latitude (a1, a2) and solar longitude for the northern (b1,b2) and southern (c1,c2) hemispheres during MYs 35 (left) and MY 37 (right). Dots over each panel indicate the solar longitude, latitude and local time of the NOMAD observations. Blue and red dots indicate morning and evening observations, respectively.