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Transcript of The Atmospheric Chemistry Experiment (ACE): Latest Results Peter Bernath Department of Chemistry,...
The Atmospheric Chemistry Experiment (ACE): Latest
ResultsPeter Bernath
Department of Chemistry, University of York
Heslington, York, UK
and
Department of Chemistry, Old Dominion University, Norfolk, VA (Aug. 2011)
The Shambles, Medieval York, UK
Norfolk Harbor, Norfolk, Virginia
ACE Mission is Applied Spectroscopy
Second edition now includes line strength formulas and their derivation for microwave (JPL), infrared (HITRAN) and electronic transitions plus light scattering.
ACE GoalsTo investigate the chemical and dynamical
processes that control the distribution of ozone in the stratosphere and upper
troposphere with a particular focus on the Arctic winter stratosphere.
To accomplish this, Temperature and pressure will be measured. ACE will measure the concentrations of
more than 30 molecules as a function of altitude.
Aerosols will be measured and quantified.
ACE Satellite
Bernath et al., GRL, 32, L15S01 (2005)
http://www.ace.uwaterloo.ca/
Solar Occultation
Advantages: 1.Radiance of sun gives higher S/N than emission2.Limb view gives longer path length ~500 km (lower detection limits) than nadir (but lower horizontal resolution)3.“Self-calibrating” so excellent long-term accuracy and precisionDisadvantages: 1.Modest global coverage2.Samples only free troposphere (>5 km or so)
Timeline (“faster, cheaper”)
Jan. 1998 Proposal to Can. Space Agency (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
First ACE data Feb. 2004, mission currently approved to March 2012. Mission had a planned 2-year lifetime – eighth anniversary Aug. 2011.
Curtis Rinsland
Instruments
Infrared Fourier Transform Spectrometer operating between 2 and 13 microns (750-4400 cm-1) 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
Optical Layout (ABB-Bomem)
Secondaymirror (6)
Field stop (5)
IR Filter(7)
Suntrackermirror (1)
Aperturestop (4)
PV MCTDetector
(18)
Glare stop(16)
Coolerwindow (17)
Outputcondenser
(14)
INTcorner-cubemirror (10)
End mirror(13)
INTcorner-cubemirror (11)
(12)
(9)
(12): Reflective coating(9): B/S coating
Beamsplit ter/compensatorassembly (8)
Primary mirror (3)
Fold mirror(22)
Lenses(23)
0.525 mimager (28)
1.02 mimager (26)
Dichroic(24)
Solarinput
Compensator
VIS/NIR-Quad CellDichroic
Quad Cell(21)
Lenses(20)
LaserMetrologyDetection
1.02 mfilter (25)
0.525 mfilter (27)
Beam splitter
Foldmirror(15) Laser Metrology Insertion
MAESTROInterface (2)
PV InSbDetector
Lens
Lens Glare stop
Dichroic
1.55 mfilter (19)
ACE-FTS (ABB-Bomem)
Interferometer-side Input optics-side
Integration to S/C Bus (DFL, Ottawa)
Pegasus XL Launch Vehicle (Aug. 12, 2003)
ACE Orbit- Global Coverage
650 km, 74° inclined circular orbit
Global Occultation Distribution
FTS – Decontamination Results
After 6 months operationAfter decontamination
Ryan Hughes
750-4400 cm-1
SNR>300 in
2 s scan
Occultation Sequence
NB: retrieved tangent height
ACE-FTS Version 3 SpeciesTracers: H2O, O3, N2O, NO, NO2, HNO3, N2O5, H2O2, HO2NO2, N2
Halogen-containing gases: HCl, HF, ClONO2, CFC-11, CFC-12, CFC-113, COF2, COCl2, COFCl, CF4, SF6, CH3Cl, CCl4, HCFC-22, HCFC-141b, HCFC-142b
Carbon-containing gases: CO, CH4, CH3OH, H2CO, HCOOH, C2H2, C2H4, C2H6, OCS, HCN as well as pressure and temperature from CO2 lines
Isotopologues: H218O, H2
17O, HDO, O13CO, OC18O, OC17O, O13C18O, 18OO2, O18OO, O17OO, N15NO, 15NNO, N2
18O, N217O, 13CO, C18O,
C17O, 13CH4, CH3D, OC34S, O13CS
Research species: ClO, acetone, PAN, HFC-23, etc.
Retrievals are entirely dependent on lab spectroscopy: HITRAN.
Climate Change
The Independent
21 Dec. 2006
Greenhouse Gases (IPCC)
1. CO2
2. CH4
3. N2O4. Halocarb.5. Trop. O3
6. Strat. H2O“Indirect Greenhouse Gases (GHGs)”1.CO2.NOX
3.VOCsAll can be measured by solar occultation IR spectroscopy.
ACE-FTS CO2 line near 61 km
Note: results are plotted on the raw measurement grid (unapodized).
ACE-FTS measures CO2, main greenhouse gas, but…
Temperature from relative CO2 line intensities; pressure from CO2 line absorption, assuming a constant CO2 concentration.
CO2 Profiles from ACE-FTS
Normal ACE retrieval uses constant CO2 VMR to get T, p and tangent heights. Use N2 continuum instead and then retrieve CO2 VMR in 5-25 km altitude range.
Foucher et al., ACP 9, 2873 (2009)
Lafferty et al., Appl. Opt. (1996)
ACE-FTS results for the 40°N-60°N latitude band
Foucher et al., ACP 11, 2455 (2011)
ACE 9-10 km (red)CARIBIC (blue)
CO2 Profiles from ACE for the 50°N-60°N latitude band
May 2006
July 2006
ACE (red)Carbontracker (blue)Flexpart (purple)
ACE CO2 trend 50°N-60°N latitude
Helpful to add observed CO2
profile information to total column
observations.
Atmospheric CCl4
G
From Geoff Toon; Note line mixing in CO2 Q-branch
CO2 line mixing H2O non-Voigt line shapes
First Global CCl4 Distribution
70S 60S 40S 20S 0 20N 40N 60N 80N
10
15
20
25
30
10
10
20
2020
30
30
40
40
50
50
60
60
70
70
8080
90
90
100
100
110
110
120130
120
20
120
Latitude (in degree)
Alt
itu
de
(in
km
)
2004-7 Latitudinal Distribution for CCl4 (in ppt)
0
20
40
60
80
100
120
N. Allen et al., ACP 9, 7449 (2009)
CCl4 produces Cl2CO peak in stratosphere
Atmospheric Phosgene, Cl2CO
Toon et al., GRL 28, 2835 (2001)ν5 (C-Cl antisymmetic
stretching mode) at849 cm-1
observed with MkIVballoon-borne FTS.
Global Distribution of Phosgene, Cl2CO
Latitude (in Degrees)
Alt
itu
de
(in
Km
)
2004-2005-2006 COCl2 Volume Mixing Ratio (in pptv)
-80 -60 -40 -20 0 20 40 60 800
5
10
15
20
25
30
35
40
0
10
20
30
40
50
60
D. Fu et al., GRL 34, L17815 (2007)
-10 0 10 20 30 400
5
10
15
20
25
30
Volume Mixing Ratio (in pptv)
Alt
itu
de
(in
km
)
85oS-60oS
60oS-30oS
30oS-30oN
30oN-60oN
60oN-90oNWilson et al. 1988Kindler et al. 1995
50oN-80oN
0o-90oN
0o-85oS
Cl ClC
Oװ
Halogen Budget and Trends
Species Global Warming Potential(20 year time horizon)
Carbon Dioxide 1Methane 72
Nitrous Oxide 289CFC - 11 6,730CFC - 12 11,000
CFC - 113 6,540Carbon Tetrachloride 2,700
HCFC - 22 5,160HCFC - 141b 2,250HCFC - 142b 5,490HFC - 134a 3,830
Sulphur Hexafluoride 16,300Carbon Tetrafluoride
(PFC - 14) 5,210
Retrievals v. 3.0: CFC-11, CFC-12 , CFC-113, HCFC-22, HCFC-141b, HCFC-142b, CCl4, CH3Cl, CF4, SF6, (HFC-134a), F2CO, ClFCO, Cl2CO, HCl, HF, ClONO2, (ClO)
A. Brown and C. Boone
SF6
HCFC-142b (CH3CClF2)
HCFC-22 (CHClF2)
CFC-12 (CCl2F2)
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.
CO, Δv=1
OH
CO Δv=2
CH, NH, OHACE Solar Spectrum http://
www.ace.uwaterloo.ca/
Used in Leicester for IASI CO retrievals
Confusion Limit
OH v=2-1 P1(2.5)
OH v=1-0 P1(6.5)
Every bump is an atomic or molecular line: confusion limit!
IR NH Spectra
Lab: Hollow cathode emission
ACE Solar
ATMOS Solar
Improved vibration-rotation and pure rotation IR spectroscopy:OH, Bernath & Colin JMS 257, 20 (2009)NH, Ram & Bernath JMS 260, 115 (2010)CH, Colin & Bernath JMS 263, 120 (2010)
Air Quality and Biomass Burning
VOCs and Air Quality
Volatile Organic Compounds (VOCs) lead to the production of tropospheric ozone, a pollutant & GHG.
Formaldehyde in the Troposphere
Directly emitted: biomass burning, incomplete combustion, industrial emissions, emissions from vegetation
Secondary product: oxidation of most anthropogenic and biogenic hydrocarbons (including methane and isoprene)
Important role in HOx and NOy radical cycling Influence the oxidative capacity of the atmosphere Effect on the tropospheric O3 budget
Important test species in evaluating our mechanistic understanding of tropospheric oxidation reactions
Surface, aircraft, and satellite measurements
HCHO tropospheric columns (GOME, SCIAMACHY, OMI, GOME-2) used for inferring isoprene emissions
HCHO contribution to the spectrum
0,0
0,2
0,4
0,6
0,8
-0,05
0,00
0,05
2778,0 2778,2 2778,4 2778,6 2778,8
-0,05
0,00
0,05
Observed spectrum
without HCHO HCHO contribution
HCHO contributionwith HCHO
0,0
0,2
0,4
0,6
0,8
-0,10-0,050,000,050,10
2780,8 2780,9 2781,0 2781,1 2781,2 2781,3 2781,4 2781,5 2781,6-0,10-0,050,000,050,10
Observed spectrum
HCHO contributionwithout HCHO
HCHO contributionwith HCHO
6 spectral windows selected in 6 spectral windows selected in the range 2735 - 2830 cmthe range 2735 - 2830 cm-1-1 ::
2739.85 ; 2765.65 ; 2778.4 ; 2739.85 ; 2765.65 ; 2778.4 ; 2781.2 ; 2812.25 ; 2826.672781.2 ; 2812.25 ; 2826.67
Perrin et al., JQSRT 110, 700 Perrin et al., JQSRT 110, 700 (2009)(2009)
0,2
0,4
0,6
0,8
-0,05
0,00
0,05
2826,2 2826,4 2826,6 2826,8 2827,0-0,05
0,00
0,05
Observed spectrum
HCHO contributionwithout HCHO
HCHO contributionwith HCHO
Dufour et al., ACP 9, 3893 (2009)
Formaldehyde Seasonal Zonal Means
Atmospheric Dynamics: Asian Summer Monsoon Anticyclone
At 13.5 km in altitude, HCN is high over Tibet because of rapid lofting of polluted air from India and China during summer; it is lower over the Pacific Ocean because of deposition and destruction in the ocean. Randel et al., Science 328, 611 (2010).
(model)(Obs)
Fox News
Molecular Spectroscopy Facility at Rutherford
Appleton Lab
Bruker IFS 125 HR, with short path and long path coolable cells
Ethane, Propane and Acetone (3 micron region)
Harrison et al., JQSRT 111, 357 (2010)
Harrison & Bernath, JQSRT 111, 1282 (2010)
Harrison et al., JQSRT, 112, 53 (SW region) and 457 (LW region)(2011)
Harrison et al., JQSRT (2011)
Acetone Measurements
ν5 and ν16 1365 cm-1 CH3 deform. bands
~195 K
~197 K
↑ acetone
Methane Near Acetone Q-branch at 1365 cm-1
• ACE spectrum near 15 km for occultation sr10063.
• Residuals for all of the measurements in the occultation between 8 and 25 km are shown on a common plot.
• The bottom panel plots the residuals when a combination of line mixing and speed dependence is used for the CH4 lines.
Acetone Retrievals (Boone)• Narrow microwindow 1364.7
- 1367.1 cm-1 covering the Q-branch.
• Line mixing and speed-dependent Voigt parameters derived from ACE spectra.
ACE Partners (Selected)• Canada- K. Walker, J. Drummond, K. Strong, J.
McConnell, W. Evans, T. McElroy, I. Folkins, R. Martin, J. Sloan, T. Shepherd, T. Llewellyn, etc.
• USA- NASA launched ACE: C. Rinsland, L. Thomason (NASA-Langley), C. Randall (U. Colorado), M. Santee, L. Froidevaux, G. Toon, 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), etc.
• France- C. Camy-Peyret, C. Clerbaux, C. Brogniez, G. Dufour, D. Hauglustaine (Paris)
• Japan- M. Suzuki (JAXA), Y. Kasai• Sweden- G. Witt (Stockholm)
Funding: CSA, NSERC, NERC, ...
ESA-NASA ExoMars Trace Gas Orbiter
JPL will send a “copy” of ACE-FTS (called MATMOS) to Mars in 2016 to look for organic signatures of life (e.g., methane).