Global Distribution of Atmospheric Formaldehyde Deposition Correlated with Water Vapor on a Warm Early Mars
6 affiliations
- 1Institute of Science Tokyo
- 2Tohoku University
- 3University of Washington
- 4The University of Tokyo
- 5National Institute of Information and Communications Technology
- 6Royal Belgian Institute for Space Aeronomy
Abstract
On early Mars, transient warm periods during the late Noachian and early Hesperian were likely triggered by episodic inputs of reducing greenhouse gases, such as H ₂ . In such a weakly reducing atmosphere, formaldehyde (H ₂ CO), a precursor for the abiotic formation of sugars via the formose reaction, can be effectively produced. While this pathway is a candidate source for Martian organic matter, previous 1D photochemical modeling could not predict the spatial distribution of organic synthesis. In this study, we developed a lookup table of H ₂ CO production based on key atmospheric variables using a photochemical model and coupled it with a global climate model. We calculated the global distribution of the atmospheric deposition fluxes of H ₂ CO under a 2 bar CO ₂ atmosphere containing 6% H ₂ with obliquity of 40°. Our results reveal a strong positive correlation between atmospheric H ₂ CO deposition and H ₂ O vapor abundance, driven by both the enhanced photochemical production of H ₂ CO through H ₂ O photolysis and the efficient scavenging by precipitation in humid regions. Significant atmospheric deposition of H ₂ CO is observed over water bodies, including the northern ocean. Furthermore, atmospheric deposition hotspots emerge around topographic highs, such as the Tharsis and Elysium mons, due to orographic precipitation. We suggest that basins adjacent to persistently humid regions, which likely experienced H ₂ CO accumulation and subsequent organic synthesis, could be potential landing sites for future missions to investigate ancient chemical evolution and whether it led to the origin of life.
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BibTeX
@article{koyama2026global,
title = {{Global Distribution of Atmospheric Formaldehyde Deposition Correlated with Water Vapor on a Warm Early Mars}},
author = {Shungo Koyama and Arihiro Kamada and Naoki Terada and Yoshihiro Furukawa and Tatsuya Yoshida and Yuki Nakamura and Takeshi Kuroda and Ann Carine Vandaele and Shohei Aoki},
journal = {The Planetary Science Journal},
year = {2026},
month = sep,
doi = {10.3847/psj/ae9942},
url = {https://iopscience.iop.org/article/10.3847/PSJ/ae9942},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Global Distribution of Atmospheric Formaldehyde Deposition Correlated with Water Vapor on a Warm Early Mars
AU - Shungo Koyama
AU - Arihiro Kamada
AU - Naoki Terada
AU - Yoshihiro Furukawa
AU - Tatsuya Yoshida
AU - Yuki Nakamura
AU - Takeshi Kuroda
AU - Ann Carine Vandaele
AU - Shohei Aoki
PY - 2026
DA - 2026/09/30
JO - The Planetary Science Journal
DO - 10.3847/psj/ae9942
UR - https://iopscience.iop.org/article/10.3847/PSJ/ae9942
AB - On early Mars, transient warm periods during the late Noachian and early Hesperian were likely triggered by episodic inputs of reducing greenhouse gases, such as H ₂ . In such a weakly reducing atmosphere, formaldehyde (H ₂ CO), a precursor for the abiotic formation of sugars via the formose reaction, can be effectively produced. While this pathway is a candidate source for Martian organic matter, previous 1D photochemical modeling could not predict the spatial distribution of organic synthesis. In this study, we developed a lookup table of H ₂ CO production based on key atmospheric variables using a photochemical model and coupled it with a global climate model. We calculated the global distribution of the atmospheric deposition fluxes of H ₂ CO under a 2 bar CO ₂ atmosphere containing 6% H ₂ with obliquity of 40°. Our results reveal a strong positive correlation between atmospheric H ₂ CO deposition and H ₂ O vapor abundance, driven by both the enhanced photochemical production of H ₂ CO through H ₂ O photolysis and the efficient scavenging by precipitation in humid regions. Significant atmospheric deposition of H ₂ CO is observed over water bodies, including the northern ocean. Furthermore, atmospheric deposition hotspots emerge around topographic highs, such as the Tharsis and Elysium mons, due to orographic precipitation. We suggest that basins adjacent to persistently humid regions, which likely experienced H ₂ CO accumulation and subsequent organic synthesis, could be potential landing sites for future missions to investigate ancient chemical evolution and whether it led to the origin of life.
SN - 2632-3338
ER -