Quantifying the vertical transport of CHBr3 and CH2Br2 over the western Pacific

Robyn Butler, Paul I. Palmer, Liang Feng, Stephen J. Andrews, Elliot L Atlas, Lucy J. Carpenter, Valeria Donets, Neil R.P. Harris, Stephen A. Montzka, Laura L. Pan, Ross J. Salawitch, Sue M. Schauffler

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We use the GEOS-Chem global 3-D atmospheric chemistry transport model to interpret atmospheric observations of bromoform (CHBr3) and dibromomethane (CH2Br2) collected during the CAST and CONTRAST aircraft measurement campaigns over the western Pacific, January-February 2014. We use a new linearized, tagged version of CHBr3 and CH2Br2, allowing us to study the influence of emissions from specific geographical regions on observed atmospheric variations. The model describes 32 %-37 % of CHBr3 and 15 %-45 % of CH2Br2 observed variability during CAST and CONTRAST, reflecting model errors in vertical transport. The model has a mean positive bias of 30 % that is larger near the surface, reflecting errors in the poorly constrained prior emission estimates. We find using the model that observed variability of CHBr3 and CH2Br2 is driven by open ocean emissions where there is deep convection. Atmospheric variability above 6 km includes a significant contribution from coastal oceans, but it is still dominated by emissions from the open ocean and by older air masses that originate upwind. In the absence of reliable ocean emission estimates, we use a new physical age-of-air simulation to determine the relative abundance of halogens delivered by CHBr3 and CH2Br2 to the tropical transition layer (TTL). We find that 76 % (92 %) of air masses that originate from the ocean reach the TTL within two (three) atmospheric e-folding lifetimes of CHBr3 and almost all of them reach the TTL within one e-folding lifetime of CH2Br2. Over the duration of CAST and CONTRAST, and over our study region, oceans delivered a mean (range) CHBr3 and CH2Br2 mole fraction of 0.46 (0.13-0.72) and 0.88 (0.71-1.01) pptv, respectively, to the TTL, and a mean (range) Bry mole fraction of 3.14 (1.81-4.18) pptv from source gases to the upper troposphere.

Original languageEnglish (US)
Pages (from-to)13135-13153
Number of pages19
JournalAtmospheric Chemistry and Physics
Volume18
Issue number17
DOIs
StatePublished - Sep 12 2018

Fingerprint

ocean
open ocean
air mass
folding
airborne survey
geographical region
atmospheric chemistry
halogen
EOS
relative abundance
troposphere
convection
air
gas
simulation

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Butler, R., Palmer, P. I., Feng, L., Andrews, S. J., Atlas, E. L., Carpenter, L. J., ... Schauffler, S. M. (2018). Quantifying the vertical transport of CHBr3 and CH2Br2 over the western Pacific. Atmospheric Chemistry and Physics, 18(17), 13135-13153. https://doi.org/10.5194/acp-18-13135-2018

Quantifying the vertical transport of CHBr3 and CH2Br2 over the western Pacific. / Butler, Robyn; Palmer, Paul I.; Feng, Liang; Andrews, Stephen J.; Atlas, Elliot L; Carpenter, Lucy J.; Donets, Valeria; Harris, Neil R.P.; Montzka, Stephen A.; Pan, Laura L.; Salawitch, Ross J.; Schauffler, Sue M.

In: Atmospheric Chemistry and Physics, Vol. 18, No. 17, 12.09.2018, p. 13135-13153.

Research output: Contribution to journalArticle

Butler, R, Palmer, PI, Feng, L, Andrews, SJ, Atlas, EL, Carpenter, LJ, Donets, V, Harris, NRP, Montzka, SA, Pan, LL, Salawitch, RJ & Schauffler, SM 2018, 'Quantifying the vertical transport of CHBr3 and CH2Br2 over the western Pacific', Atmospheric Chemistry and Physics, vol. 18, no. 17, pp. 13135-13153. https://doi.org/10.5194/acp-18-13135-2018
Butler, Robyn ; Palmer, Paul I. ; Feng, Liang ; Andrews, Stephen J. ; Atlas, Elliot L ; Carpenter, Lucy J. ; Donets, Valeria ; Harris, Neil R.P. ; Montzka, Stephen A. ; Pan, Laura L. ; Salawitch, Ross J. ; Schauffler, Sue M. / Quantifying the vertical transport of CHBr3 and CH2Br2 over the western Pacific. In: Atmospheric Chemistry and Physics. 2018 ; Vol. 18, No. 17. pp. 13135-13153.
@article{8bcb7d7aa8f04e21ac7d149bcd9e90f8,
title = "Quantifying the vertical transport of CHBr3 and CH2Br2 over the western Pacific",
abstract = "We use the GEOS-Chem global 3-D atmospheric chemistry transport model to interpret atmospheric observations of bromoform (CHBr3) and dibromomethane (CH2Br2) collected during the CAST and CONTRAST aircraft measurement campaigns over the western Pacific, January-February 2014. We use a new linearized, tagged version of CHBr3 and CH2Br2, allowing us to study the influence of emissions from specific geographical regions on observed atmospheric variations. The model describes 32 {\%}-37 {\%} of CHBr3 and 15 {\%}-45 {\%} of CH2Br2 observed variability during CAST and CONTRAST, reflecting model errors in vertical transport. The model has a mean positive bias of 30 {\%} that is larger near the surface, reflecting errors in the poorly constrained prior emission estimates. We find using the model that observed variability of CHBr3 and CH2Br2 is driven by open ocean emissions where there is deep convection. Atmospheric variability above 6 km includes a significant contribution from coastal oceans, but it is still dominated by emissions from the open ocean and by older air masses that originate upwind. In the absence of reliable ocean emission estimates, we use a new physical age-of-air simulation to determine the relative abundance of halogens delivered by CHBr3 and CH2Br2 to the tropical transition layer (TTL). We find that 76 {\%} (92 {\%}) of air masses that originate from the ocean reach the TTL within two (three) atmospheric e-folding lifetimes of CHBr3 and almost all of them reach the TTL within one e-folding lifetime of CH2Br2. Over the duration of CAST and CONTRAST, and over our study region, oceans delivered a mean (range) CHBr3 and CH2Br2 mole fraction of 0.46 (0.13-0.72) and 0.88 (0.71-1.01) pptv, respectively, to the TTL, and a mean (range) Bry mole fraction of 3.14 (1.81-4.18) pptv from source gases to the upper troposphere.",
author = "Robyn Butler and Palmer, {Paul I.} and Liang Feng and Andrews, {Stephen J.} and Atlas, {Elliot L} and Carpenter, {Lucy J.} and Valeria Donets and Harris, {Neil R.P.} and Montzka, {Stephen A.} and Pan, {Laura L.} and Salawitch, {Ross J.} and Schauffler, {Sue M.}",
year = "2018",
month = "9",
day = "12",
doi = "10.5194/acp-18-13135-2018",
language = "English (US)",
volume = "18",
pages = "13135--13153",
journal = "Atmospheric Chemistry and Physics",
issn = "1680-7316",
publisher = "European Geosciences Union",
number = "17",

}

TY - JOUR

T1 - Quantifying the vertical transport of CHBr3 and CH2Br2 over the western Pacific

AU - Butler, Robyn

AU - Palmer, Paul I.

AU - Feng, Liang

AU - Andrews, Stephen J.

AU - Atlas, Elliot L

AU - Carpenter, Lucy J.

AU - Donets, Valeria

AU - Harris, Neil R.P.

AU - Montzka, Stephen A.

AU - Pan, Laura L.

AU - Salawitch, Ross J.

AU - Schauffler, Sue M.

PY - 2018/9/12

Y1 - 2018/9/12

N2 - We use the GEOS-Chem global 3-D atmospheric chemistry transport model to interpret atmospheric observations of bromoform (CHBr3) and dibromomethane (CH2Br2) collected during the CAST and CONTRAST aircraft measurement campaigns over the western Pacific, January-February 2014. We use a new linearized, tagged version of CHBr3 and CH2Br2, allowing us to study the influence of emissions from specific geographical regions on observed atmospheric variations. The model describes 32 %-37 % of CHBr3 and 15 %-45 % of CH2Br2 observed variability during CAST and CONTRAST, reflecting model errors in vertical transport. The model has a mean positive bias of 30 % that is larger near the surface, reflecting errors in the poorly constrained prior emission estimates. We find using the model that observed variability of CHBr3 and CH2Br2 is driven by open ocean emissions where there is deep convection. Atmospheric variability above 6 km includes a significant contribution from coastal oceans, but it is still dominated by emissions from the open ocean and by older air masses that originate upwind. In the absence of reliable ocean emission estimates, we use a new physical age-of-air simulation to determine the relative abundance of halogens delivered by CHBr3 and CH2Br2 to the tropical transition layer (TTL). We find that 76 % (92 %) of air masses that originate from the ocean reach the TTL within two (three) atmospheric e-folding lifetimes of CHBr3 and almost all of them reach the TTL within one e-folding lifetime of CH2Br2. Over the duration of CAST and CONTRAST, and over our study region, oceans delivered a mean (range) CHBr3 and CH2Br2 mole fraction of 0.46 (0.13-0.72) and 0.88 (0.71-1.01) pptv, respectively, to the TTL, and a mean (range) Bry mole fraction of 3.14 (1.81-4.18) pptv from source gases to the upper troposphere.

AB - We use the GEOS-Chem global 3-D atmospheric chemistry transport model to interpret atmospheric observations of bromoform (CHBr3) and dibromomethane (CH2Br2) collected during the CAST and CONTRAST aircraft measurement campaigns over the western Pacific, January-February 2014. We use a new linearized, tagged version of CHBr3 and CH2Br2, allowing us to study the influence of emissions from specific geographical regions on observed atmospheric variations. The model describes 32 %-37 % of CHBr3 and 15 %-45 % of CH2Br2 observed variability during CAST and CONTRAST, reflecting model errors in vertical transport. The model has a mean positive bias of 30 % that is larger near the surface, reflecting errors in the poorly constrained prior emission estimates. We find using the model that observed variability of CHBr3 and CH2Br2 is driven by open ocean emissions where there is deep convection. Atmospheric variability above 6 km includes a significant contribution from coastal oceans, but it is still dominated by emissions from the open ocean and by older air masses that originate upwind. In the absence of reliable ocean emission estimates, we use a new physical age-of-air simulation to determine the relative abundance of halogens delivered by CHBr3 and CH2Br2 to the tropical transition layer (TTL). We find that 76 % (92 %) of air masses that originate from the ocean reach the TTL within two (three) atmospheric e-folding lifetimes of CHBr3 and almost all of them reach the TTL within one e-folding lifetime of CH2Br2. Over the duration of CAST and CONTRAST, and over our study region, oceans delivered a mean (range) CHBr3 and CH2Br2 mole fraction of 0.46 (0.13-0.72) and 0.88 (0.71-1.01) pptv, respectively, to the TTL, and a mean (range) Bry mole fraction of 3.14 (1.81-4.18) pptv from source gases to the upper troposphere.

UR - http://www.scopus.com/inward/record.url?scp=85053286163&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85053286163&partnerID=8YFLogxK

U2 - 10.5194/acp-18-13135-2018

DO - 10.5194/acp-18-13135-2018

M3 - Article

AN - SCOPUS:85053286163

VL - 18

SP - 13135

EP - 13153

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

SN - 1680-7316

IS - 17

ER -