title: Atmospheric deposition of methanol over the Atlantic Ocean.
abstract: In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air-sea methanol transfer along a ∼10,000-km north-south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air-sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at ∼5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface-an important term for improving air-sea gas exchange models.
authors.affiliation: Plymouth Marine Laboratory, Plymouth PL1 3DH, United Kingdom.
authors.forename: Mingxi
authors.initials: M
authors.lastname: Yang
authors.forename: Philip D
authors.initials: PD
authors.lastname: Nightingale
authors.forename: Rachael
authors.initials: R
authors.lastname: Beale
authors.forename: Peter S
authors.initials: PS
authors.lastname: Liss
authors.forename: Byron
authors.initials: B
authors.lastname: Blomquist
authors.forename: Christopher
authors.initials: C
authors.lastname: Fairall
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001267:Atlantic Ocean; D001272:Atmosphere / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D000432:Methanol / Q000032:analysis*; D008956:Models, Chemical; D012623:Seawater / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D000432:Methanol
keywords: air–sea exchange; eddy covariance; environmental chemistry; marine micrometeorology; trace gas cycling