Comment on “Phosphine in the Venusian Atmosphere: A Strict Upper Limit From SOFIA GREAT Observations” by Cordiner et al.
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Geophysical Research Letters - 2023 - Greaves - Comment on Phosphine in the Venusian Atmosphere A Strict Upper Limit From.pdf
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Author(s)
Greaves, Jane S
Petkowski, Janusz J
Richards, Anita MS
Sousa‐Silva, Clara
Seager, Sara
Clements, David L
Date Issued
December 6, 2023
Journal
Geophysical Research Letters
Publisher
American Geophysical Union
Citation
Greaves, Jane S, Petkowski, Janusz J, Richards, Anita MS, Sousa‐Silva, Clara, Seager, Sara et al. 2023. "Comment on “Phosphine in the Venusian Atmosphere: A Strict Upper Limit From SOFIA GREAT Observations” by Cordiner et al.." Geophysical Research Letters, 50 (23).
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Final published version
Abstract
Searches for phosphine in Venus' atmosphere have sparked a debate. Cordiner et al. (2022, https://doi.org/10.1029/2022gl101055) analyze spectra from the Stratospheric Observatory For Infrared Astronomy (SOFIA) and infer <0.8 ppb of PH3. We noticed that some spectral artifacts arose from non-essential calibration-load signals. By-passing these signals allows simpler post-processing and a 5.7σ candidate detection, suggesting ∼3 ppb of PH3 above the clouds. Compiling six phosphine results hints at an inverted abundance trend: decreasing above the clouds but rising again in the mesosphere from some unexplained source. However, no such extra source is needed if phosphine is undergoing destruction by sunlight (photolysis), to a similar degree as on Earth. Low phosphine values/limits are found where the viewed part of the super-rotating Venusian atmosphere had passed through sunlight, while high values are from views moving into sunlight. We suggest Venusian phosphine is indeed present, and so merits further work on models of its origins.
Description
Article relates to: Cordiner, M. A., Villanueva, G. L., Wiesemeyer, H., Milam, S. N., dePater, I., Moullet, A., et al. (2022). Phosphine in the Venusian atmosphere: A strict upper limit from SOFIA GREAT observations. Geophysical Research Letters, 49, e2022GL101055. https://doi.org/10.1029/2022GL101055
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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DOI of Published Version
10.1029/2023gl103539
