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An improved oceanic budget for methyl chloride
Author(s) -
Hu Lei,
YvonLewis Shari A.,
Butler James H.,
Lobert Jürgen M.,
King Daniel B.
Publication year - 2013
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2012jc008196
Subject(s) - anomaly (physics) , flux (metallurgy) , salinity , saturation (graph theory) , sea surface temperature , seawater , solubility , wind speed , atmospheric sciences , environmental science , climatology , temperature salinity diagrams , chemistry , geology , oceanography , physics , mathematics , organic chemistry , combinatorics , condensed matter physics
We present results that improve the estimates of the global net sea‐to‐air flux, global oceanic emission, global oceanic uptake, and partial atmospheric lifetime of methyl chloride (CH 3 Cl) with respect to oceanic loss. This study includes improved parameterizations for solubility and saturation anomaly‐sea surface temperature relationships for CH 3 Cl, along with the use of an updated gas transfer velocity from a recent study. By measuring solubilities of CH 3 Cl in pure water and seawater over a temperature range from 0°C to 40°C, we obtained a new solubility function with both temperature and salinity dependencies. We also developed a new parameterization of seasonal CH 3 Cl saturation anomaly ( ∆ %) as a function of both sea surface temperature and wind speed using data from 10 different cruises with an extensive coverage in the global surface ocean. Using the new solubility function and the new seasonal ∆ %‐(SST, wind speed) relationships, we estimated the global net sea‐to‐air flux of CH 3 Cl at 335 (210 to 480) Gg yr −1 . For the first time, the global flux of CH 3 Cl was broken into a unidirectional gross emission and a unidirectional gross uptake, which were estimated at 700 (510 to 910) Gg yr −1 and −370 (−430 to −300) Gg yr −1 . The partial atmospheric lifetime of CH 3 Cl with respect to the oceanic uptake was revised to 12 (10–15) years, resulting in a revision on the atmospheric lifetime of CH 3 Cl from the previous estimate of 1.0 year to 1.2 years.