| Literature DB >> 29880682 |
Christopher R Webster1, Paul R Mahaffy2, Sushil K Atreya3, John E Moores4, Gregory J Flesch5, Charles Malespin2, Christopher P McKay6, German Martinez3, Christina L Smith4, Javier Martin-Torres7,8, Javier Gomez-Elvira9, Maria-Paz Zorzano7,9, Michael H Wong3, Melissa G Trainer2, Andrew Steele10, Doug Archer11, Brad Sutter11, Patrice J Coll12, Caroline Freissinet13, Pierre-Yves Meslin14, Raina V Gough15, Christopher H House16, Alexander Pavlov2, Jennifer L Eigenbrode2, Daniel P Glavin2, John C Pearson5, Didier Keymeulen5, Lance E Christensen5, Susanne P Schwenzer17, Rafael Navarro-Gonzalez18, Jorge Pla-García9,19, Scot C R Rafkin20, Álvaro Vicente-Retortillo3, Henrik Kahanpää21, Daniel Viudez-Moreiras9, Michael D Smith2, Ari-Matti Harri21, Maria Genzer21, Donald M Hassler20, Mark Lemmon22, Joy Crisp5, Stanley P Sander5, Richard W Zurek5, Ashwin R Vasavada5.
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.Entities:
Year: 2018 PMID： 29880682 DOI： 10.1126/science.aaq0131
Source DB: PubMed Journal: Science ISSN： 0036-8075 Impact factor: 47.728