A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer

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A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer. / Carpenter, Lucy; Bloss, William; Andrews, Stephen; Lidster, Richard; Saiz-Lopez, Alfonso; Fernandez-Sanchez, Miguel; Ouyang, Bin; Jones, Roderic.

In: Journal of Atmospheric Chemistry, 25.09.2015.

Research output: Contribution to journalArticle

Harvard

Carpenter, L, Bloss, W, Andrews, S, Lidster, R, Saiz-Lopez, A, Fernandez-Sanchez, M, Ouyang, B & Jones, R 2015, 'A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer', Journal of Atmospheric Chemistry. https://doi.org/10.1007/s10874-015-9320-6

APA

Carpenter, L., Bloss, W., Andrews, S., Lidster, R., Saiz-Lopez, A., Fernandez-Sanchez, M., Ouyang, B., & Jones, R. (2015). A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer. Journal of Atmospheric Chemistry. https://doi.org/10.1007/s10874-015-9320-6

Vancouver

Author

Carpenter, Lucy ; Bloss, William ; Andrews, Stephen ; Lidster, Richard ; Saiz-Lopez, Alfonso ; Fernandez-Sanchez, Miguel ; Ouyang, Bin ; Jones, Roderic. / A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer. In: Journal of Atmospheric Chemistry. 2015.

Bibtex

@article{95ac53c4a4694f4f9bf285bead29be04,
title = "A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer",
abstract = "Ocean emissions of inorganic and organic iodine compounds drive the biogeochemical cycle of iodine and produce reactive ozone-destroying iodine radicals that influence the oxidizing capacity of the atmosphere. Di-iodomethane (CH2I2) and chloro-iodomethane (CH2ICl) are the two most important organic iodine precursors in the marine boundary layer. Ship-borne measurements made during the TORERO (Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOC) field campaign in the east tropical Pacific Ocean in January/February 2012 revealed strong diurnal cycles of CH2I2 and CH2ICl in air and of CH2I2 in seawater. Both compounds are known to undergo rapid photolysis during the day, but models assume no night-time atmospheric losses. Surprisingly, the diurnal cycle of CH2I2 was lower in amplitude than that of CH2ICl, despite its faster photolysis rate. We speculate that night-time loss of CH2I2 occurs due to reaction with NO3 radicals. Indirect results from a laboratory study under ambient atmospheric boundary layer conditions indicate a k CH2I2+NO3 of ≤4 × 10−13 cm3 molecule−1 s−1; a previous kinetic study carried out at ≤100 Torr found k CH2I2+NO3 of 4 × 10−13 cm3 molecule−1 s−1. Using the 1-dimensional atmospheric THAMO model driven by sea-air fluxes calculated from the seawater and air measurements (averaging 1.8 +/− 0.8 nmol m−2 d−1 for CH2I2 and 3.7 +/− 0.8 nmol m−2 d−1 for CH2ICl), we show that the model overestimates night-time CH2I2 by >60 % but reaches good agreement with the measurements when the CH2I2 + NO3 reaction is included at 2–4 × 10−13 cm3 molecule−1 s−1. We conclude that the reaction has a significant effect on CH2I2 and helps reconcile observed and modeled concentrations. We recommend further direct measurements of this reaction under atmospheric conditions, including of product branching ratios.",
author = "Lucy Carpenter and William Bloss and Stephen Andrews and Richard Lidster and Alfonso Saiz-Lopez and Miguel Fernandez-Sanchez and Bin Ouyang and Roderic Jones",
year = "2015",
month = sep,
day = "25",
doi = "10.1007/s10874-015-9320-6",
language = "English",
journal = "Journal of Atmospheric Chemistry",
issn = "0167-7764",
publisher = "Springer",

}

RIS

TY - JOUR

T1 - A nocturnal atmospheric loss of CH2I2 in the remote marine boundary layer

AU - Carpenter, Lucy

AU - Bloss, William

AU - Andrews, Stephen

AU - Lidster, Richard

AU - Saiz-Lopez, Alfonso

AU - Fernandez-Sanchez, Miguel

AU - Ouyang, Bin

AU - Jones, Roderic

PY - 2015/9/25

Y1 - 2015/9/25

N2 - Ocean emissions of inorganic and organic iodine compounds drive the biogeochemical cycle of iodine and produce reactive ozone-destroying iodine radicals that influence the oxidizing capacity of the atmosphere. Di-iodomethane (CH2I2) and chloro-iodomethane (CH2ICl) are the two most important organic iodine precursors in the marine boundary layer. Ship-borne measurements made during the TORERO (Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOC) field campaign in the east tropical Pacific Ocean in January/February 2012 revealed strong diurnal cycles of CH2I2 and CH2ICl in air and of CH2I2 in seawater. Both compounds are known to undergo rapid photolysis during the day, but models assume no night-time atmospheric losses. Surprisingly, the diurnal cycle of CH2I2 was lower in amplitude than that of CH2ICl, despite its faster photolysis rate. We speculate that night-time loss of CH2I2 occurs due to reaction with NO3 radicals. Indirect results from a laboratory study under ambient atmospheric boundary layer conditions indicate a k CH2I2+NO3 of ≤4 × 10−13 cm3 molecule−1 s−1; a previous kinetic study carried out at ≤100 Torr found k CH2I2+NO3 of 4 × 10−13 cm3 molecule−1 s−1. Using the 1-dimensional atmospheric THAMO model driven by sea-air fluxes calculated from the seawater and air measurements (averaging 1.8 +/− 0.8 nmol m−2 d−1 for CH2I2 and 3.7 +/− 0.8 nmol m−2 d−1 for CH2ICl), we show that the model overestimates night-time CH2I2 by >60 % but reaches good agreement with the measurements when the CH2I2 + NO3 reaction is included at 2–4 × 10−13 cm3 molecule−1 s−1. We conclude that the reaction has a significant effect on CH2I2 and helps reconcile observed and modeled concentrations. We recommend further direct measurements of this reaction under atmospheric conditions, including of product branching ratios.

AB - Ocean emissions of inorganic and organic iodine compounds drive the biogeochemical cycle of iodine and produce reactive ozone-destroying iodine radicals that influence the oxidizing capacity of the atmosphere. Di-iodomethane (CH2I2) and chloro-iodomethane (CH2ICl) are the two most important organic iodine precursors in the marine boundary layer. Ship-borne measurements made during the TORERO (Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOC) field campaign in the east tropical Pacific Ocean in January/February 2012 revealed strong diurnal cycles of CH2I2 and CH2ICl in air and of CH2I2 in seawater. Both compounds are known to undergo rapid photolysis during the day, but models assume no night-time atmospheric losses. Surprisingly, the diurnal cycle of CH2I2 was lower in amplitude than that of CH2ICl, despite its faster photolysis rate. We speculate that night-time loss of CH2I2 occurs due to reaction with NO3 radicals. Indirect results from a laboratory study under ambient atmospheric boundary layer conditions indicate a k CH2I2+NO3 of ≤4 × 10−13 cm3 molecule−1 s−1; a previous kinetic study carried out at ≤100 Torr found k CH2I2+NO3 of 4 × 10−13 cm3 molecule−1 s−1. Using the 1-dimensional atmospheric THAMO model driven by sea-air fluxes calculated from the seawater and air measurements (averaging 1.8 +/− 0.8 nmol m−2 d−1 for CH2I2 and 3.7 +/− 0.8 nmol m−2 d−1 for CH2ICl), we show that the model overestimates night-time CH2I2 by >60 % but reaches good agreement with the measurements when the CH2I2 + NO3 reaction is included at 2–4 × 10−13 cm3 molecule−1 s−1. We conclude that the reaction has a significant effect on CH2I2 and helps reconcile observed and modeled concentrations. We recommend further direct measurements of this reaction under atmospheric conditions, including of product branching ratios.

U2 - 10.1007/s10874-015-9320-6

DO - 10.1007/s10874-015-9320-6

M3 - Article

JO - Journal of Atmospheric Chemistry

JF - Journal of Atmospheric Chemistry

SN - 0167-7764

ER -