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Quantifying the contribution of marine organic gases to atmospheric iodine
Author(s) -
Jones Charlotte E.,
Hornsby Karen E.,
Sommariva Roberto,
Dunk Rachel M.,
von Glasow Roland,
McFiggans Gordon,
Carpenter Lucy J.
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl043990
Subject(s) - cape verde , iodine , flux (metallurgy) , seawater , environmental science , environmental chemistry , atmospheric chemistry , atmospheric sciences , oceanography , chemistry , geology , ozone , ethnology , organic chemistry , history
Oceanic emissions of gaseous organic iodine‐atom precursors have the potential to significantly affect atmospheric chemistry and climate, however there is currently considerable uncertainty associated with quantifying their sources. We present sea‐air fluxes calculated from simultaneous air and seawater measurements of a comprehensive range of volatile organic iodine compounds (VOICs), including CH 3 I and the less commonly reported dihalomethanes CH 2 ICl, CH 2 IBr and CH 2 I 2 , made during two cruises in the Atlantic Ocean between 15–58°N. The combined dihalomethane flux provides a global iodine source (∼0.33 ± 0.19 Tg I y −1 ) comparable to that of CH 3 I, and a surface iodine atom source 3–4 times higher. However, a 1D atmospheric model reveals that, in the tropical east Atlantic Ocean in the vicinity of Cape Verde, even these combined VOIC fluxes are capable of supporting only ∼10–25% of the observed IO levels, and suggests that a substantial (340–640 nmol I m −2 d −1 ) additional photochemical source of iodine is required.