Observations of BrO and (HOBr+Br2) by GT-CIMS during CONTRAST 2014

Dexian Chen, Greg Huey, David Tanner GaTech

Andrew Weinheimer, Denise Montzka, Teresa Campos, L. Kaser NCAR

Teresa Campos, Mike ReevesMeghan Stell, Janine Aquino, and Frank Flocke NCAR

Eric Apel, Rebecca Hornbrook, Alan Hills NCARDaniel Riemer U MiamiNicola Blake UC Irvine

Elliot Atlas, Sue Schauffler, Valeria Donets , R. Lube U Miami

and CONTRAST team

CIMS

Chemical Ionization Mass Spectrometer

Measurements:BrO+I-BrO·I- (m/z=222, 224)HOBr+I-HOBr·I- (m/z=223, 225)Br2+I-Br2·I- (m/z=285, 287, 289)

(HOBrBr2 , report the sum of HOBr+Br2)

Flow Tube (reactor) Mass Spec.inlet

CIMS

Chemical Ionization Mass Spectrometer

Calibrations:• Online: periodically flowed cal gas (Br2, Cl2)

into the CIMS• Offline: compared sensitivities of BrO, HOBr to

sensitivities of the cal gas (in the lab)

Flow Tube (reactor) Mass Spec.inlet

Cal Gas

Measurement Issues

During the field campaign we became concerned that Br2 calibration gas could contaminate inlet walls.

i.e. Br2 BrO

Problem alleviated by switching to Cl2 calibration gas at RF09.

For now only reporting data for RF09-RF16

Very high O3 levels may also lead to BrO artifact during RF15. Needs work but more importantly comparison to DOAS data.

Most of the time…

0.6

0.4

0.2

0.0

-0.2

-0.4

BrO

/ppt

01:002014/2/17

02:00 03:00

dat

14x103

12

10

8

6

4

2

ALT/m

BrO/ppt ALT/m

Levels of BrO and HOBr+Br2 near the limits of detection (LOD)

LOD for BrO, 0.3-1.5 pptLOD of HOBr+Br2, 0.5-2 ppt

e.g., RF12 (2/16-2/17)

16

14

12

10

8

6

4

2

LAT

152150148146144142LON

14x103

12

10

8

6

4

2

0

ALT

/m

RF10(2/8)Flight GoalSample a large pollution plume

GUAM

1.0

0.8

0.6

0.4

0.2

0.0

00:302014/2/8

01:00 01:30 02:00

dat

6

4

2

0

-2

BrO

or (H

OB

r+B

r 2)/pp

t

14x103

12

10

8

6

4

2

ALT/m

BrO/ppt HOBr+Br2/ppt ALT

RF10 (2/8)

160

140

120

100

80

60

40

CH

3CN

/ppt

00:002014/2/8

00:30 01:00 01:30

dat

14x103

12

10

8

6

4

2

0

ALT/m

1.0

0.8

0.6

0.4

0.2

0.0

CH3CN/ppt ALT/m

1.0

0.8

0.6

0.4

0.2

0.0

00:002014/2/8

00:30 01:00 01:30 02:00

dat

140

120

100

80

60

40

20

0

CO

or O

3 /p

pb

14x103

12

10

8

6

4

2

0

ALT/m

CO/ppb O3/ppb ALT/m

1.0

0.8

0.6

0.4

0.2

0.0

00:302014/2/8

01:00 01:30 02:00

dat

200

150

100

50

NO

or N

O2

/ppt

14x103

12

10

8

6

4

2

ALT/m

NO/ppt NO2/ppt ALT/m

1.0

0.8

0.6

0.4

0.2

0.0

00:002014/2/8

00:30 01:00 01:30 02:00

dat

600

400

200

0

AC

ETO

NE

or H

CN

/ppt

14x103

12

10

8

6

4

2

ALT/m

Acetone/ppt HCN/ppt ALT/m

RF11 (02/12-0213)Flight GoalSample the O3 layer south of GuamSample convective outflow

1.0

0.8

0.6

0.4

0.2

0.0

00:002014/2/13

00:30 01:00 01:30 02:00

dat

6

4

2

0

BrO

or H

OB

r+B

r 2 /p

pt

14x103

12

10

8

6

4

2

ALT/m

BrO/ppt HOBr/ppt ALT/m

GUAM

13

12

11

10

9

8

7

LAT

146144142140138136134132130LON

14x103

12

10

8

6

4

2

0

ALT

/m

RF11 (02/12-0213)1.0

0.8

0.6

0.4

0.2

0.0

00:002014/2/13

00:30 01:00 01:30

dat

120

100

80

60

40

20

O3

or C

O/p

pb

14x103

12

10

8

6

4

2

ALT/m

CO/ppb O3/ppb ALT/m

1.0

0.8

0.6

0.4

0.2

0.0

00:002014/2/13

01:00 02:00 03:00

dat

200

150

100

50

H2O(v)/ppm

14x103

12

10

8

6

4

2

0

ALT/m

H2O(v)/ppm ALT/m

500

400

300

200

100

AC

ETO

NE

or H

CN

/ppt

00:002014/2/13

01:00 02:00

dat

14x103

12

10

8

6

4

2

ALT/m

1.0

0.8

0.6

0.4

0.2

0.0

Acetone/ppt HCN/ppt ALT/m

RF15 (2/24-2/25)Flight GoalTransect to Japan

1.0

0.8

0.6

0.4

0.2

0.0

00:002014/2/25

03:00 06:00

dat

15

10

5

0

BrO

or (H

OB

r+B

r 2)/pp

t

14x103

12

10

8

6

4

2

0

ALT/m

BrO/ppt HOBr+Br2/ppt ALT/m

40

35

30

25

20

15

10

LAT

150149148147146145144LON

14x103

12

10

8

6

4

2

0

ALT

/m

GUAM

Spike in BrO w/o increase in HOBr?

RF15(02/24)1.0

0.8

0.6

0.4

0.2

0.0

00:002014/2/25

03:00 06:00

dat

800

600

400

200

O3/

ppb

5.0

4.5

4.0

3.5

3.0

H2 O(v)/ppm

14x103

12

10

8

6

4

2

ALT/m

O3/ppb H2O(v)/ppm ALT

240

230

220

210

200

190

CFC

_11/

ppt

00:002014/2/25

03:00 06:00

dat

14x103

12

10

8

6

4

2

ALT/m

1.0

0.8

0.6

0.4

0.2

0.0

CFC_11 (CCl3F)/ppt ALT Br_key

Summary

Most of the time no significant levels of BrO and (HOBr+Br2) were observed

There were a limited number of enhanced layers of BrO and HOBr. They correspond to either stratospheric air or tropospheric air impacted by biomass/pollution.

Ongoing work…

Comparisons needed with DOAS to confirm elevated BrO levels and to investigate possible high ozone issue. RF15, RF11, RF10, and transit are high priorities.

Compare stratospheric BrO/HOBr to model calculations.

Investigate origins of high tropospheric signals

Transit (2/28-3/1)GOAL OF FLIGHTTransit(Honolulu- Boulder)

40

35

30

25

20

-150 -140 -130 -120 -110

12x103

10

8

6

4

2

0

ALT

/m

1.0

0.8

0.6

0.4

0.2

0.0

02:002014/3/1

03:00 04:00 05:00

dat

25

20

15

10

5

0

BrO

or

(HO

Br+

Br 2

)/pp

t

12x103

10

8

6

4

2

ALT/m

BrO/ppt HOBr+Br2/ppt ALT/m

Transit flight(02/28-03/01)1.0

0.8

0.6

0.4

0.2

0.0

02:002014/3/1

03:00 04:00 05:00

dat

800

600

400

200

O3/ppb

5.0

4.5

4.0

3.5

3.0

H2 O(v)/p

pm

12x103

10

8

6

4

2

0

ALT/m

O3/ppb H2O(v)/ppm ALT

O3: Weinheimer et alWater vapor: GV platform

CIMS

Chemical Ionization Mass Spectrometry

backgroundingThree way valve (periodical measurements

mode and background mode)

Flow Tube (reactor) Mass Spectinlet

Charcoal filter

Offline calibrations in the Lab (BrO)

Br2+O32BrO

(Liao et al., 2011)

CIMSBr2

CIMSBr2+O3

350⁰C

Offline calibrations in the Lab(HOBr)

HOBr+NaBr(het)Br2

(Liao et al., 2011)

CIMS

HOBr soln.

NaBr salt bed

N2 HOBr(g)

Limit of Detection (LOD)• X