Transcript PicoSDLA-CH 4 - Copernicus.org

Development of PicoSDLA laser sensors for in-situ
measurements of CH4,
CO2 and H2O in the UTLS in the frame of the TROpico project.
M. GHYSELS1, J. COUSIN1, N. AMAROUCHE3, L. GOMEZ-MARTIN1,
E. D. RIVIERE1, G. DURRY1,2
1 Groupe
de Spectrométrie Moléculaire et Atmosphérique, GSMA,
UMR CNRS 7331
UFR Sciences Exactes et Naturelles, BP 1039, 51687 REIMS
Cedex 2
2 IPSL, Laboratoire Atmosphères, Milieux, Observations Spatiales,
UMR CNRS 8190, 78280 Guyancourt, France
3 Division technique de l'Institut National des Sciences de l'Univers,
1, place Aristide Briand, 92195, Meudon Cedex, France.
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Scientific context
Sources of methane:
+ 150%
• Anthropogenic : Fossils fuels
production, rice cultivation,
biomass burning, waste
management, etc…
• Natural : Wetland, non-wetland
soil, gas hydrates, premafrost,
termites, oceans, etc…
More than 50% of methane emission come from humanrelated activities
On per molecule basis, 25 times more efficient radiatively
than CO2 molecule
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Water vapor and methane in the
stratosphere
O3 depletion during winter 2011
In the tropics : Deep convection
permits injection of species in the
stratosphere by overshooting
convection or slow ascent in the
TTL
Oxidation of CH4 in stratosphere:
CH4 + OH  CH3 + H2O
Methane in stratosphere: source of water vapor
Winter at poles: In the stratosphere, PSC formation → Ozone
depletion
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TRO-Pico balloon campaign
(PI. E. D. Rivière, GSMA)
Main Objective : Characterization of
overshoots in order to quantify their impact on
the hydratation of low stratosphere
(regional → global scale)
•Cirrus formation, impact of electrically charged particules on
TTL
•Validation of satellites measurements of water vapour of
IASI/Metop and SAPHIR/Megha-tropiques
•Variability of low stratosphere humidity : regular sounding of
water vapour
Launchs from Bauru (Brazil, 22°S)
Collaboration: l’IPMet-UNESP
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Development of PicoSDLA-CH4 :
scientific objectives
PicoSDLA-CH4 ~15 kg : L= 3.6 m
SDLA [Durry and G. Megie, (1999)]
Total weight ~80 kg, L = 56m
PicoSDLA-CH4 :
• Precision <5%
• Measurement time reduced:
10 ms to 1 s (measurement under
parachutes, speed ≈ 15 m.s-1)
• Regular soundings under small
meteorological balloons
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PicoSDLA-CH4
optical path lenght :
3.6 m
M. GHYSELS, GSMA
SDLA spectrometer,
optical path lenght : 56m
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Based on direct absorption spectroscopy :
F0
F
Laser
Détector
Determination of mixing ratio from Beer-Lambert law :
(low absorption hypothesis)
F
Amol ( )   S (Tatmos )   (Tatmos , Patmos ,  )  L  NCH 4
F0
S(Tatmos) : Line strenght [cm-1/molec cm-2]
φ(Tatmos, Patmos, σ) : Line profile
L : Optical path lenght [cm]
NCH4 : Number of molecules
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CDFG
Laser
module
Optical
fiber
Signal
diode
PPLN
crystal
Pump
diode
Laser head
Novawave Technologies
(Dr. J. JOST), Inc. (USA)
20 cm x 12 cm x 2.5 cm,
980g
1.5 µm
3.24 µm
1 µm
Output power ≈ 10µW
Continuous coverage: 3076 to 3096
cm-1
DFG laser source → access to the R(6) transition of the ν3 band
of CH4 (3086 cm-1, 3.24 µm)
Strong fundamental band → Reduction of optical path
lenght: 56m → 3.6 m
In laboratory, determination of spectroscopic parameter
(uncertainty <2%)
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PicoSDLA-CH4
sensor
Gold coating
retroreflector
Laser head
Detector
Germanium filter
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2 balloon campaigns:
• ENRICHED, Kiruna 2011.
Successfull test flight the 1st of April
inside the polar vortex
ComparisonTWIN/ PicoSDLA
→ good agreement
Precision : 5% at 20km
1.
PicoSDLA-CH4 onboard TWIN
10-3
(PI A. Engels, University of Frankfurt)
LOD 2. 10-4
M. Ghysels et al, Ap. Phys. B,104, Issue 4 (2011), Page 9891000.
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Kiruna
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TRO-Pico Bauru (Brazil, 22°S) 1 scientific flight
14th of March 2012
Preliminary results :
Temperature (°C)
CH4,
R(6) manifold,
ν band,
Alt: 22.6
km 20
-80
-60
-40 3
-20
0
1,000
Pressure (mbar)
Transmission
0,998
0,996
PicoSDLA-CH4 flight
14th of March 2012 (Bauru)
0,994
0,992
ρCH4 = 1.42 ± 0.05 ppmv
Temperature
3085,9
3085,8
PicoSDLA-CH4
before flight
(Bauru, 2012)
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Pressure (mbar)
100
3086,0
Observed
Calculated
3086,1
3086,2
-1
Pico-SDLA CH
ascent
Wavenumber
(cm )
4
1000
1,4
1,5
1,6
1,7
1,8
1,9
Mixing ratio (ppmv)
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Sensor PicoSDLA-H2O
1 m path lenght, 10kg weight
TRO-Pico : 3 flights (march 2012)
ENRICHED (2011): comparison with
ELHYSA (PI. G. Berthet, LPC2E, Orléans)
→ good agreement
Date of the flight
Remarks
9th of March
Need more work
for data process
11th of March
Successfull,
overshooting?
13th of March
Sucessfull,
convective
conditions during
the flight. Need
more analysis
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1m
PicoSDLA-H2O , Bauru 2012
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Preliminary results
Temperature (°C)
-80
13th
-70
-60
-50
-40
-30
th
11 of March
th
13 of March
March 2012
Pressure (mbar)
40
60
80
Signature of
overshoots ?
100
120
140
160
180
200
1E-6
1E-5
Mixing ratio
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PicoSDLA-CO2
Calibration in laboratory:
• Long time measurements (4h) from calibrated mixing of
carbon dioxide and dry air
• Allan variance : τAllan = 980 s, σ Allan = 280 ppbv
Precision ≈ 1ppmv for 1s averaging time
Calibrated value : 503.9 ppmv
Calculated value : (502.6 ± 2.2) ppmv
4h
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PicoSDLA-CO2 flights
Objective : Lack of observations of
the CO2 concentration’s decrease
throught the UTLS [S. Park et al.
(2010)]
About ≈ 10 ppmv (mid-latitudes)
•ENRICHED balloon campaign from
Kiruna (67°N) : 1 flight the12th of
March 2011
•Shortly : TRO-Pico balloon campaign
from Bauru (22°S), 2 flights
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Conclusion
ENRICHED :
Intercomparison TWIN/ PicoSDLA-CH4 → good agreement
Intensities (uncertainty <2%), γself determined
Actually, temperature dependance of γair
Validation of PicoSDLA-H2O by intercomparison
ELHYSA/PicoSDLA
Test flight of PicoSDLA-CO2
TRO-Pico :
PicoSDLA-CH4 : 1 flights and 1 future flight (Jan-Feb of 2013).
PicoSDLA-H2O : 3 flights, 2 flights in convective conditions
future: 15 background flights and 4 convective flights
PicoSDLA-CO2: 2 flights (in convective conditions)
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Thank you for attention
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