Atmospheric methanol budget and ocean implication

Brian G. Heikes, Wonil Chang, Michael E.Q. Pilson, Elijah Swift, Hanwant B. Singh, Alex Guenther, Daniel J. Jacob, Brendan D. Field, Ray Fall, Daniel Reimer, Larry Brand

Research output: Contribution to journalArticle

131 Scopus citations

Abstract

Methanol is a biogeochemically active compound and a significant component of the volatile organic carbon in the atmosphere. It influences background tropospheric photochemistry and may serve as a tracer for biogenic emissions. The mass of methanol in the atmospheric reservoir, the annual mass flux of methanol from sources to sinks, and the estimated atmospheric lifetime of methanol in the free troposphere, marine boundary layer, continental boundary layer, and in-cloud, are evaluated. The atmosphere contains approximately 4 Tg (terragrams, 1012 g) of methanol. Estimates of global methanol sources and sinks total 340 and 270 Tg methanol yr-1, respectively, and are in balance given their estimated precision. Sink terms were evaluated using observed methanol distributions; the total loss is approximately a factor of 5 larger than prior estimates. The adopted source is a factor of 3 larger than its prior estimate. Recent net flux observations and the magnitude of the estimated sink suggest biogenic methanol emissions to be near their current estimated upper limit, >280 Tg methanol yr-1, and this value was adopted. The methanol source will be larger with the inclusion of an argued for oceanic gross emission of 30 Tg methanol yr-1, but a major uncertainty concerns whether the oceans are a major net sink or source of methanol, an issue which will not be resolved without new measurements. Other large uncertainties are the estimates of primary biogenic emissions and gas surface deposition. The first loss estimates of methanol by in-cloud chemistry and precipitation are presented. They are approximately equal at 10 Tg methanol yr-1, each. These are small in comparison to the surface loss and gas phase photochemical loss estimated here but would be significant additional losses in earlier budgets. Surface exchange processes dominate the atmospheric budget of methanol and its distribution. The atmospheric deposition of methanol and the argued for methanol produced in the upper ocean are ubiquitous sources of C1 substrate capable of sustaining methylotrophic organisms throughout the surface ocean.

Original languageEnglish (US)
Pages (from-to)80-1-80-13
JournalGlobal Biogeochemical Cycles
Volume16
Issue number4
DOIs
StatePublished - Dec 2002

Keywords

  • Atmosphere
  • Methanol
  • Ocean
  • OVOC
  • Oxygenated hydrocarbons

ASJC Scopus subject areas

  • Global and Planetary Change
  • Atmospheric Science
  • Environmental Science(all)
  • Environmental Chemistry

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    Heikes, B. G., Chang, W., Pilson, M. E. Q., Swift, E., Singh, H. B., Guenther, A., Jacob, D. J., Field, B. D., Fall, R., Reimer, D., & Brand, L. (2002). Atmospheric methanol budget and ocean implication. Global Biogeochemical Cycles, 16(4), 80-1-80-13. https://doi.org/10.1029/2002gb001895