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Background levels of methane in Mars' atmosphere show strong seasonal variations.

Authors :
Webster CR
Mahaffy PR
Atreya SK
Moores JE
Flesch GJ
Malespin C
McKay CP
Martinez G
Smith CL
Martin-Torres J
Gomez-Elvira J
Zorzano MP
Wong MH
Trainer MG
Steele A
Archer D Jr
Sutter B
Coll PJ
Freissinet C
Meslin PY
Gough RV
House CH
Pavlov A
Eigenbrode JL
Glavin DP
Pearson JC
Keymeulen D
Christensen LE
Schwenzer SP
Navarro-Gonzalez R
Pla-García J
Rafkin SCR
Vicente-Retortillo Á
Kahanpää H
Viudez-Moreiras D
Smith MD
Harri AM
Genzer M
Hassler DM
Lemmon M
Crisp J
Sander SP
Zurek RW
Vasavada AR
Source :
Science (New York, N.Y.) [Science] 2018 Jun 08; Vol. 360 (6393), pp. 1093-1096.
Publication Year :
2018

Abstract

Variable levels of methane in the martian atmosphere have eluded explanation partly because the measurements are not repeatable in time or location. We report in situ measurements at Gale crater made over a 5-year period by the Tunable Laser Spectrometer on the Curiosity rover. The background levels of methane have a mean value 0.41 ± 0.16 parts per billion by volume (ppbv) (95% confidence interval) and exhibit a strong, repeatable seasonal variation (0.24 to 0.65 ppbv). This variation is greater than that predicted from either ultraviolet degradation of impact-delivered organics on the surface or from the annual surface pressure cycle. The large seasonal variation in the background and occurrences of higher temporary spikes (~7 ppbv) are consistent with small localized sources of methane released from martian surface or subsurface reservoirs.<br /> (Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Details

Language :
English
ISSN :
1095-9203
Volume :
360
Issue :
6393
Database :
MEDLINE
Journal :
Science (New York, N.Y.)
Publication Type :
Academic Journal
Accession number :
29880682
Full Text :
https://doi.org/10.1126/science.aaq0131