observations of bro and (hobr+br 2 ) by gt-cims during contrast 2014 dexian chen, greg huey, david...
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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
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