Atmospheric Chemistry Experiment
(ACE):
Recent Results
Peter Bernath (and ACE team)
Department of Chemistry, University of York
Heslington, York, UK
and
Department of Chemistry, University of
Waterloo, Waterloo, ON, Canada
ACE Satellite
See
http://www.ace.uwaterloo.ca
Solar Occultation
Advantages:
Radiance of sun gives higher S/N than emission
Limb view gives longer path length ~500 km (lower detection limits)
than nadir
“Self-calibrating” so excellent long-term accuracy and precision
Disadvantages:
Modest global coverage
Samples only free troposphere
Timeline















Jan.
1998
Proposal to CSA
Feb. 2001
FTS and Imager CDR
Mar. 2001
MAESTRO CDR
Jun.
2001
Bus CDR
Sept.
2002
S/C integration & test
Mar. 2003
Instrument test (Toronto)
May
2003
Final integration (DFL)
Aug.
2003
Launch
Sept.
2003
Commissioning
Feb.
2004
Routine operations
Mar.
2004
Arctic campaign
Feb.
2005
Arctic campaign
Feb.
2006
Arctic campaign
Feb.
2007
Arctic campaign
Feb.
2008
Arctic campaign
First ACE data Feb. 2004, mission currently
approved to March 2010. Mission had a 2year lifetime – fifth anniversary Aug. 2008.
Instruments
 Infrared Fourier Transform Spectrometer
operating between 2 and 13 microns with a
resolution of 0.02 cm-1
 2-channel visible/near infrared Imagers, operating
at 0.525 and 1.02 microns (cf., SAGE II)
 Suntracker keeps the instruments pointed at the
sun’s radiometric center.
 UV / Visible spectrometer (MAESTRO) 0.4 to 1.03
microns, resolution ~1-2 nm
 Startracker
Bernath et al. GRL, 32, L15S01 (2005)
SCISAT-1 Spacecraft (Bristol)
Key Specifications
Spacecraft diameter
Spacecraft mass
Pointing control:
Pitch/yaw (3 )
Roll (3 )
Pointing knowledge:
Pitch/yaw
Roll
Solar array EOL power
Spacecraft OA power
Bus reliability (2-yrs)
Mass memory
112 cm
152 kg
± 0.2º
± 0.7º
± 0.1º
± 0.6º
175 W
75 W
80 %
1.5 Gb
Optical Layout (ABB-Bomem)
INT
corner-cube
INT
corner-cube
mirror (11)
mirror (10)
Beamsplitter/
compensator
assembly (8)
(12): Reflective coating
(9): B/S coating
(12)
Laser
Metrology
Detection
(9)
End mirror
(13)
IR Filter
(7)
O utp ut
c onde ns er
(14)
(15)
C o ole r
w ind ow (17)
D i chroi c
1.02 m
G l are s top
(16)
Lens
(18)
Laser Metrology Insertion
1.02 m Dichroic
Lenses
filter (25)
(24)
(23)
Seconday
Fold mirror
mirror (6)
(22)
imager (26)
G lare sto p
0.525 m
Lens
PV M C T
D ete cto r
Beam splitter
Compensator
Fold
mirror
Field stop (5)
0.525 m
filter (27)
Ap erture
s top (4)
imager (28)
P V InS b
Suntracker
mirror (1)
Lenses
(20)
D etec tor
VIS/NIR-Quad Cell
Dichroic
Quad Cell
(21)
1.55 m
filter (19)
MAESTRO
Primary mirror (3)
Interface (2)
Solar
input
MAESTRO
MAESTRO
PI:
T. McElroy,
MSC
Dual concave grating spectrograph, 1-2 nm resolution
Global Occultation Distribution
FTS – Decontamination
Results
After 6 months operation
After decontamination
Ryan Hughes
Occultation sequence
ACE-FTS Species Measured
 Baseline species (version 2.2):
H2O, O3, N2O, CO, CH4, NO, NO2, HNO3, HF, HCl, N2O5,
ClONO2, CCl2F2, CCl3F, as well as pressure and temperature
from CO2 lines
 Other routine species:
COF2, CHF2Cl, CF4, CH3Cl, C2H6, SF6, OCS, HCN
 Research species:
CCl4, HOCl, H2O2, HO2NO2, CCl2FCClF2, CH3CClF2, ClO, C2H2,
C2H6, COFCl, COCl2, CH3OH, HCOOH, H2CO, N2 and additional
isotopologues
CO2 line near 61 km
Typical ACE-FTS
fitting results
Note: results are
plotted on the raw
measurement grid
Boone et al. Appl.
Opt. 44, 7218 (2005)
Temperature Retrievals-CO2
90 km
Schwartz
et al. JGR,
113,
D15S11
(2008)
15 km
Stratospheric Chlorine Budget
Northern Midlatitudes
Southern Midlatitudes
Nassar et al.
WMO Ozone
Report 2006
JGR, 111,
D22312
(2006)
Current
HALOE value
3.3 ppb
Northern high latitudes
Northern midlatitudes
Tropics
Southern midlatitudes
Southern high latitudes
Mean ClTOT (ppbv)
3.74 ± 0.12
3.65 ± 0.09
3.62 ± 0.11
3.65 ± 0.09
3.71 ± 0.16
slope (ppbv/km)
0.010 ± 0.001
0.007 ± 0.001
0.009 ± 0.001
0.007 ± 0.001
0.014 ± 0.001
CFC-11, CFC-12 , HCFC-22, CCl4, CH3Cl, CF4, CFC-113, HCFC-142b, HFC134a, F2CO, ClFCO, Cl2CO
Asian Monsoon Anticyclone
Park et al., ACP, 8,
757 (2008)
Global Distribution of Phosgene,
Cl2CO
Fu et al. GRL, 34, L17815 (2007) (Toon et
al.’s calculated linelist for ν5 near 850 cm-1)
Cl
O
‫װ‬
C
2004-2005-2006 COCl2 Volume Mixing Ratio (in pptv)
40
60
30
35
50
25
30
20
30
15
20
20
Altitude (in km)
Altitude (in Km)
40
25
15
o
o
60 S-30 S
o
30 S-30oN
10
30oN-60oN
o
o
o
o
60 N-90 N
Wilson et al. 1988
Kindler et al. 1995
10
10
85oS-60oS
5
5
50 N-80 N
0o-90oN
o
o
0 -85 S
0
-80
-60
-40
-20
0
20
Latitude (in Degrees)
40
60
80
0
0
-10
0
10
20
Volume Mixing Ratio (in pptv)
30
40
Cl
Distribution of COClF
• Carbonyl
chlorofluoride is a
product of
chlorofluorocarbon
(CFC-11 mainly)
decomposition
• Previously studied by
aircraft (5 - 12 km)
• First global picture
obtained from ACEFTS
• Spectroscopy based
on Brown’s ATMOS
linelist created from
Kitt Peak spectra,
with rough
intensities.
D. Fu et al., to be submitted
Effect of Lightning (HNO3)
Lightning produces
NO, which is
oxidized to HNO3.
Need to have 6 Tg
N/yr from
lightning to match
ACE observations
of tropospheric
HNO3 (Martin et
al. JGR, 112,
D09309 (2007))
ACE Solar Spectrum
CH, NH, OH
OH
CO
Δv=2
CO, Δv=1
ACE solar spectrum (F. Hase): 224782 spectra added, improvement over ATMOS, no
telluric lines, but 0.02 cm-1 vs 0.01 cm-1 resolution (resolution largely determined by
width of solar lines) and 750-4400 cm-1 vs 600-4800 cm-1.
ATMOS Spacelab-3, 1985
New atomic and
molecular
assignments
(ACE linelist) by
L. Wallace
(NOAO);
improved
spectroscopic
data for CH, NH
and OH.
ATMOS ATLAS-3, 1994
For OH, Reg
Colin (ULB) finds
v=4 can be
improved.
ACE, 2008
Air Quality and Biomass Burning
Biomass Burning in Brazil
17
16
15
14
a ltitu d e (k m )
13
12
11
s s 6 1 3 9 - v 2 .1
C O *0 .0 1
10
9
O 3 *0 .0 1
8
HCN
7
C 2H 6
6
5
0 .0
0 .5
1 .0
1 .5
2 .0
v m r (p p b v )
MODIS Fire
Counts
26 Sept. 2004
27 Sept. 2004
28 Sept. 2004
2 .5
3 .0
3 .5
CH3OH contribution to the spectrum
Dufour et al.
ACP, 6, 3463
(2006); data
from Xu et al.
2004
Global Methanol
ACE is an upper tropospheric “air quality” mission measuring
global CH4, CH3OH, HCN, C2H2, C2H6, H2O2, HCOOH, H2CO, plus
likely PAN and acetone.
Dufour et al. ACP,
7, 6119, 2007
LDMz-INCA model
(D. Hauglustaine)
Young Biomass Burning Plume
Transmittance
1.00
0.98
1.00
1.00
0.98
0.98
0.00
0.00
C2H4
-0.05
950
951
-0.02
965
Coheur et al. ACP, 7, 547, 2007
966
967
-0.05
1140
PAN
1150
1160
1170
1180
-1
Wavenumber (cm )
1.00
1.00
Transmittance
NH3
1.00
0.95
0.95
0.95
0.90
0.90
0.00
0.00
0.00
-0.05
1364
1365
1366
-0.05
1367 2778
C3H4
H2CO
C 3H 6O
-0.05
2782
2780
-1
Wavenumber (cm )
3320
3321
PAN, Peroxyacetyl nitrate, etc.
Coheur et al. (Brussels), PAN from a
biomass plume near East Africa
CO and OVOCs
CH4 and NMHCs
CH4 (× 1/1000)
20
CO (× 1/50)
HCOOH
CH3OH
C2H6
C3H4 (× 10)
HNO3
CH3COO2NO2 (PAN)
HCN
NH3 (× 10)
C3H6O
C2H4 (× 10)
18
Nitrogen species
H2CO (× 10)
C2H2
Altitude (km)
16
14
12
10
8
6
0.0
0.5
1.0
1.5
2.0
0
1
2
vmr (ppbv)
3
4 0.0
0.5
1.0
HCHO spectroscopy: new linelist
Use of HCHO line intensities calculated by A. Perrin
1 213 18-203 17
5 80 8-81 7
1 221 22-211 21
1,0
Dufour
et al.
Missing lines
Transmittance
0,8
0,6
Error with
multiplets
Obs
0,4
Calc New calc
Calc with HITRAN*1.28
0,2
Obs-Calc New Calc
0,0
2831,6
2831,7
2831,8
2831,9
Wavenumber in cm
Perrin, Jacquemart, Kwabia-Tchana & Lacome
2832,0
-1
2832,1
2832,2
HCHO contribution to the spectrum
0,8
6 spectral windows selected in the
range 2735 - 2830 cm-1 :
2739.85 ; 2765.65 ; 2778.4 ;
2781.2 ; 2812.25 ; 2826.67
0,8
Observed spectrum
0,6
0,4
0,2
0,0
0,10
without HCHO
0,05
0,00
-0,05
-0,10
0,10
with HCHO
0,05
0,00
-0,05
-0,10
2780,8 2780,9 2781,0
Observed spectrum
0,6
HCHO contribution
HCHO contribution
2781,1
2781,2
2781,3
2781,4
2781,5
2781,6
0,8
Observed spectrum
0,4
0,6
0,2
0,4
0,0
0,05
without HCHO
HCHO contribution
0,2
0,00
0,05
-0,05
0,05
HCHO contribution
with HCHO
0,00
-0,05
0,05
-0,05
2778,0
2778,2
2778,4
2778,6
2778,8
without HCHO
HCHO contribution
with HCHO
HCHO contribution
0,00
0,00
-0,05
2826,2
2826,4
2826,6
2826,8
2827,0
3 years of HCHO measurements with ACE-FTS
Preliminary comparisons with
CTMs
120
110
HCHO vmr (pptv)
100
90
8.5 km
LMDz-INCA
ACE-FTS
GEOS-CHEM
North America
r = 0.96
r = 0.93
80
70
60
50
40
30
20
HCHO vmr (pptv)
10
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
MAM04
HCHO vmr (pptv)
90
80
SON04
DJF05
MAM05
JJA05
SON05
DJF06
MAM06
JJA06
SON06
South Hemisphere:
LMDz-INCA systematically smaller
MAM04
100
JJA04
Europe-Russia
r = 0.98
r = 0.93
Comparison with 2 state-of-theart models (LMDz-INCA and
GEOS-Chem) that use different
emissions inventories.
North Hemisphere:
seasonality of UT HCHO well
reproduced
intensity of the maximum not
always reproduced
JJA04
SON04
DJF05
MAM05
JJA05
SON05
DJF06
MAM06
JJA06
SON06
SON04
DJF05
MAM05
JJA05
SON05
DJF06
MAM06
JJA06
SON06
South Tropics
r = 0.0
r = 0.38
70
60
50
40
30
MAM04
JJA04
South Tropics:
small impact of biomass burning
larger variability in the models
ACE Partners (Selected)
 Canada- K. Walker, J. Drummond, K. Strong, J. McConnell, W.
Evans, T. McElroy, I. Folkins, R. Martin, J. Sloan, T. Shepherd,
etc.
 USA- NASA launched ACE: C. Rinsland, L. Thomason (NASALangley), C. Randall (U. Colorado), B. Bojkov (NASA-Goddard),
M. Santee, L. Froidevaux, G. Manney (JPL), etc.
 Belgium- supplied CMOS imager chips: R. Colin, P.-F. Coheur, M.
Carleer (ULB), D. Fussen, M. DeMaziere (IASB), M. Mahieu, R.
Zander (Liege), etc.
 UK- J. Remedios (Leicester), P. Palmer (Edinburgh), M.
Chipperfield (Leeds)
 France- C. Camy-Peyret, C. Clerbaux, C. Brogniez, G. Dufour, D.
Hauglustaine (Paris)
 Japan- M. Suzuki, Y. Kasai (JAXA)
 Sweden- G. Witt (Stockholm)
Sunset over Kitt Peak, AZ