a new interpretation of total column bro during arctic spring

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

[email protected]

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




Aura Science Team Meeting, 28 September 2010 2

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

[email protected]

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:






Aircraft & Satellite Observations of BrO



Satellite hotspots believed to be associated with surface release of bromine that

causes nearly complete removal of ozone



Geographic regions of near surface ozone depletion and elevated BrOx

generally not co-located with hotspots in OMI total column BrO (BrOVC)


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


OMI Total Column O3

Tropopause Pressure


6 Apr 2008




OMI Total Column O3

Tropopause Pressure


7 Apr 2008




OMI Total Column O3

Tropopause Pressure


8 Apr 2008




OMI Total Column O3

Tropopause Pressure


9 Apr 2008



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


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




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



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


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


OMI Total Column O3

Tropopause Pressure


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


OMI Total Column O3

Tropopause Pressure


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


OMI Total Column O3

Tropopause Pressure


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


OMI Total Column O3

Tropopause Pressure


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


OMI Total Column O3

Tropopause Pressure


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

Aura Science Team Meeting, 28 September 2010 21 21

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


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?


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



DC-8 flight track


Enhanced Tropospheric BrO

occurs at altitudes well above

top of the convective boundary

layer: another surprising finding



DC-8 flight track


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


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


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


Backup Slides


Validation


OMI Fitting Window


BrO+NO2 Rate Constant


Barrow BrO


VSL Bry


Box and Whisker Plot


BrO Table

a new interpretation of total column bro during arctic spring

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