a new interpretation of total column bro during arctic spring
TRANSCRIPT
A New Interpretation of Total Column BrO
During Arctic Spring
Ross Salawitch, Tim Canty, Thomas Kurosu, Kelly Chance, Qing Liang,
Arlindo da Silva, Steven Pawson, Eric Nielsen, Jose Rodriguez,
P.K. Bhatia, Xiong Liu, Greg Huey, Jin Liao, Robert Stickel, David Tanner, Jack Dibb,
Bill Simpson, Deanna Donohoue, Andrew Weinheimer, Frank Flocke,
David Knapp, Denise Montzka, Andy Neuman, John Nowak,
Thomas Ryerson, Samuel Oltmans, Donald Blake, Elliot Atlas, Doug Kinnison,
Simone Tilmes, Laura Pan, Francois Hendrick,Michel Van Roozendael,
Karin Kreher, Paul Johnston, Ru-Shan Gao, Bryan Johnson, Paul Bui,
Gao Chen,R. Bradley Pierce, James Crawford, Daniel Jacob
ARCTAS
Will show data from:
• 4 research aircraft (DC8, GV, P3, WB57)
• collected during 4 missions (ARCPAC, ARCTAS, START08, TC4)
and :
• 1 satellite instrument (OMI)
This work is in press at Geophys. Res. Lett. Frontier, available at:
http://www.agu.org/journals/pip/gl/2010GL043798-pip.pdf
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A New Interpretation of Total Column BrO
During Arctic Spring
Ross Salawitch, Tim Canty, Thomas Kurosu, Kelly Chance, Qing Liang,
Arlindo da Silva, Steven Pawson, Eric Nielsen, Jose Rodriguez,
P.K. Bhatia, Xiong Liu, Greg Huey, Jin Liao, Robert Stickel, David Tanner, Jack Dibb,
Bill Simpson, Deanna Donohoue, Andrew Weinheimer, Frank Flocke,
David Knapp, Denise Montzka, Andy Neuman, John Nowak,
Thomas Ryerson, Samuel Oltmans, Donald Blake, Elliot Atlas, Doug Kinnison,
Simone Tilmes, Laura Pan, Francois Hendrick,Michel Van Roozendael,
Karin Kreher, Paul Johnston, Ru-Shan Gao, Bryan Johnson, Paul Bui,
Gao Chen,R. Bradley Pierce, James Crawford, Daniel Jacob
ARCTAS
Will show data from:
• 4 research aircraft (DC8, GV, P3, WB57)
• collected during 4 missions (ARCPAC, ARCTAS, START08, TC4)
and :
• 1 satellite instrument (OMI)
Study includes:
• ground-based data from Alaska, Norway, and New Zealand
• three dimensional calculations from GEOS–5 and WACCM
• many email messages !
This work is in press at Geophys. Res. Lett. Frontier, available at:
http://www.agu.org/journals/pip/gl/2010GL043798-pip.pdf
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Aircraft & Satellite Observations of BrO
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Aircraft & Satellite Observations of BrO
Satellite hotspots believed to be associated with surface release of bromine that
causes nearly complete removal of ozone
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Aircraft & Satellite Observations of BrO
Geographic regions of near surface ozone depletion and elevated BrOx
generally not co-located with hotspots in OMI total column BrO (BrOVC)
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
5 Apr 2008
Locations of hotspots in OMI total column BrO are consistent with total column ozone and tropopause height,
suggesting a stratospheric origin to these regions of elevated BrO
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
6 Apr 2008
Locations of hotspots in OMI total column BrO are consistent with total column ozone and tropopause height,
suggesting a stratospheric origin to these regions of elevated BrO
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
7 Apr 2008
Locations of hotspots in OMI total column BrO are consistent with total column ozone and tropopause height,
suggesting a stratospheric origin to these regions of elevated BrO
Aura Science Team Meeting, 28 September 2010 9
OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
8 Apr 2008
Locations of hotspots in OMI total column BrO are consistent with total column ozone and tropopause height,
suggesting a stratospheric origin to these regions of elevated BrO
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
9 Apr 2008
Locations of hotspots in OMI total column BrO are consistent with total column ozone and tropopause height,
suggesting a stratospheric origin to these regions of elevated BrO
We presented these types of relations at prior Aura Science Team meetings. Our focus in the past year has been: 1) quantification of BrO above the tropopause using 3D models 2) reconciliation of budget for total column BrO based on: a. OMI total column; b. model strat column; c. aircraft trop column 3) writing up the results
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Bromine from VSL (very short lived) Sources
TC4 tropospheric data indicate significant potential for VSL species to supply Bry to stratosphere
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Bromine from VSL (very short lived) Sources
TC4 tropospheric data indicate significant potential for VSL species to supply Bry to stratosphere
ARCTAS stratospheric data show presence of larger amounts of VSL bromocarbons
in Arctic lowermost stratosphere (this is a surprising finding!)
Local Source Gas Injection
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Bromine from VSL (very short lived) Sources
TC4 tropospheric data indicate significant potential for VSL species to supply Bry to stratosphere
ARCTAS stratospheric data show presence of larger amounts of VSL bromocarbons
in Arctic lowermost stratosphere (this is a surprising finding!)
Local Source Gas Injection Bry also affected by Tropical Source Gas Injection & Product Gas Injection
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Bromine from VSL (very short lived) Sources
Qing Liang is mow estimating supply of ~7 ppt of Bry
to the stratosphere solely by CH2Br2 and CHBr3
Please see her poster for the details
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Calculated & measured CFC-12 agree to within ~4%
Model Input 3D fields of CFC-12 from GEOS-5 used to specify baseline Bry
BrO/Bry ratio obtained from START 08 run of WACCM
Model Output BrO, for SZA of OMI overpass, for 3 cases: VSL Bry = 0, 5, & 10 ppt
Modeling Stratospheric BrO
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
VSL=0 ppt VSL=5 ppt
Mo
de
l S
trato
sp
heri
c
Co
lum
n B
rO
5 Apr 2008
VSL=10 ppt 16
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
VSL=0 ppt VSL=5 ppt
Mo
de
l S
trato
sp
heri
c
Co
lum
n B
rO
6 Apr 2008
VSL=10 ppt 17
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
VSL=0 ppt VSL=5 ppt
Mo
de
l S
trato
sp
heri
c
Co
lum
n B
rO
7 Apr 2008
VSL=10 ppt 18
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
VSL=0 ppt VSL=5 ppt
Mo
de
l S
trato
sp
heri
c
Co
lum
n B
rO
8 Apr 2008
VSL=10 ppt 19
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OMI Total Column O3
Tropopause Pressure
OMI Total Column BrO
VSL=0 ppt VSL=5 ppt
Mo
de
l S
trato
sp
heri
c
Co
lum
n B
rO
9 Apr 2008
VSL=10 ppt 20
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Model BrO depends on accuracy of kinetics that govern BrO/Bry ratio
Reactions considered: Br+HO2
Br+O3
BrO+NO
BrO+NO2
Br+H2CO
JBrNO3
JHOBr
Model Uncertainty
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Observation and Model Uncertainties
Considerable overlap between OMI total column BrO and
stratospheric model when uncertainties are considered
What about contributions to column BrO from the troposphere?
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29 Tropospheric BrO Profiles Observed During ARCPAC and ARCTAS OMI Total Column Model Strat Col (VSL=10 ppt)
DC-8 flight track
See Neuman et al., Atmos. Chem. Phys., 2010 for detailed discussion of the tropospheric BrO measurements
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29 Tropospheric BrO Profiles Observed During ARCPAC and ARCTAS OMI Total Column Model Strat Col (VSL=10 ppt)
DC-8 flight track
See Neuman et al., Atmos. Chem. Phys., 2010 for detailed discussion of the tropospheric BrO measurements
Enhanced Tropospheric BrO
occurs at altitudes well above
top of the convective boundary
layer: another surprising finding
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29 Tropospheric BrO Profiles Observed During ARCPAC and ARCTAS OMI Total Column Model Strat Col (VSL=10 ppt)
DC-8 flight track
See Neuman et al., Atmos. Chem. Phys., 2010 for detailed discussion of the tropospheric BrO measurements
Enhanced Tropospheric BrO
occurs at altitudes well above
top of the convective boundary
layer: another surprising finding
This finding is supported by
ground based Max DOAS
observations from Barrow
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Reconciliation of Budget for Total Column BrO
Good news:
Measured Trop BrO + Modeled Strat BrO agrees with OMI total BrO,
provided VSL Bry is between ~5 and 10 ppt !
Bad news:
Uncertainties prevent precise determination of VSL Bry
We believe the VSL Bry = 0 ppt case is not consistent with the data, despite
fact slope lies close to unity (within uncertainties), because this model
lacks strong features that track column O3 & tropopause pressure
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Conclusions • Location of numerous OMI BrO hotspots during Arctic spring consistent
with observations of total column O3, tropopause height, and modeled strat BrO provided VSL bromocarbons supply 5 to 10 ppt of Bry
• Community has likely overestimated scale and frequency of tropospheric perturbations due to “bromine explosion” by associating all satellite hotspots with this phenomena
• Next step: calculation of tropospheric residual BrO
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Backup Slides
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Validation
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OMI Fitting Window
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BrO+NO2 Rate Constant
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Barrow BrO
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VSL Bry
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Box and Whisker Plot
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BrO Table