Spectroscopic study of CH 4 at 3.24 µm for atmospheric applications. Development of the PicoSDLA-CH 4 sensor and the TRO-Pico balloon campaign M. GHYSELS 1, J. COUSIN 1, L. GOMEZ 1,N. AMAROUCHE 3, E. D. RIVIERE 1, H. TRAN 4, G. DURRY 1,2 1 Groupe de Spectrométrie Moléculaire et Atmosphérique, GSMA, UMR CNRS 7331 UFR Sciences Exactes et Naturelles, BP 1039, 51687 REIMS Cedex 2, France 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 4 Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA, UMR CNRS 7583), Université Paris XII, Avenue du Général de Gaulle, Batiment 350, 94010 Créteil Cedex, France M. Ghysels et al, ASA/HITRAN 2012 1
Why measuring methane? Methane is a tracer : convection, isentropic transport. Application: TRO Pico campaign in Brazil Methane is a greenhouse gas (it s contribution may increase in the future) Methane is a source of water vapor in the stratosphere by oxidation process. Indirect impact on the ozone layer. Validation of space mission dedicated to methane is needed (ex: LIDAR Merlin) M. Ghysels et al, ASA/HITRAN 2012 2
Why the PicoSDLA- CH4 compact sensor? PicoSDLA-CH 4 onboard TWIN (PI A. Engels, University of Frankfurt) to increase flight opportunities by releasing launch constraints : to be flown under weather balloons. to be flown as piggy back onboard larger gondola. M. Ghysels et al, ASA/HITRAN 2012 3
SDLA Weight : 80 kg L = 56 at 1.65 µm PicoSDLA-CH 4 Weight : 15kg L = 3.6 m at 3.24 µm SDLA L = 56 m at 1.65 µm (2000) 2000 2010 In situ measurements Direct absorption spectroscopy Collaboration with DT-INSU (Meudon) PicoSDLA-CH 4 : Precision <5% Measurement time <1s Weight < 15kg M. Ghysels et al, ASA/HITRAN 2012 4
M. Ghysels et al, ASA/HITRAN 2012 5
Optical cell Gold coating retroreflector DFG Laser head Detector Germanium filter M. Ghysels et al, ASA/HITRAN 2012 6
CDFG Laser module Laser head Optical fiber Novawave Technologies (Dr. J. JOST), Inc. (USA) 20 cm x 12 cm x 2.5 cm 980g Signal diode Pump diode DFG laser source 1.5 µm 1 µm PPLN crystal 3.24 µm DFG laser source R(6) transition ν 3 band of CH 4 (3086 cm -1, 3.24 µm, MIR) Strong fundamental band Reduction of optical path lenght : 56m 3.6 m M. Ghysels et al, ASA/HITRAN 2012 7
Balloon campaigns M. Ghysels et al, ASA/HITRAN 2012 8
Kiruna 2011 In the frame of ENRICHED project : 1 test flight as piggy back onboard TWIN experiment PicoSDLA-CH 4 onboard TWIN (PI A. Engels, University of Frankfurt) 9
1. 10-3 10 ms 20 km Atmospheric spectra P = 49.02 hpa T = -69.89 C (1.49 ± 0.01)ppmv Precision : 5% at 20km (elementary spectra) 12 km M. Ghysels et al, ASA/HITRAN 2012 10
TRO-Pico, Brazil 1 scientific flight, 14th march 2012 Data process underway Flight under small balloon during convection PicoSDLA-CH 4 TRO-Pico, march 2012 M. Ghysels et al, ASA/HITRAN 2012 11
Spectroscopic study M. Ghysels et al, ASA/HITRAN 2012 12
Why spectroscopy? Objectif : To Process balloon datas During flight : temperature range from 293 to 203 K Experiment : from 293 to 213K (limitation for cooling) M. Ghysels et al, ASA/HITRAN 2012 13
Temperature dependence of line coefficients Determination of γ air, β air, ζ air and temperature dependence Study on R(6) manifold, ν 3 band of CH 4 Collaboration with Ha Tran (LISA, Créteil) and Laura Gomez (INTA, Espagne) Home-made laser source M. Ghysels et al, ASA/HITRAN 2012 14
M. Ghysels et al, ASA/HITRAN 2012 15 ) ), ( 1 ), ( Im ), ( 1 ), ( (Re 1 ln 2 ) ( + + + + + = Φ z y s x w z z y s x w z y s x w z z y s x w x m D π ς π γ π Hard-LM profile Line-mixing [Pine, 1996] Rautian Hard-LM Rautian Line-mixing at low pressures 30 hpa Ambient temperature R(6) in air Experimental spectrum
Position (cm 1 ) γ air (T ref ) (1/atm) This work n γ γ air (295K) (1/atm) Pine 3085.83 0.0590 ± 0.0008 0.75 ± 0.10 0.0583 +1.2 3085.86 0.0612 ± 0.001 0.98 ± 0.10 0.0613 0.2 3085.89 0.0644 ± 0.002 0.90 ± 0.15 0.0630 +2.2 3086.03 0.0563 ± 0.002 0.76 ± 0.16 0.0568 0.8 3086.07 0.0592 ± 0.002 0.79 ± 0.20 0.0598 1.0 3086.08 0.0547 ± 0.0003 0.79 ± 0.05 0.0509 +7.5 Rel. Dif (%) Results Position (cm 1 ) β air (T ref ) (1/atm) This work n β β air (295K) (1/atm) Pine 3085.83 0.0227 ± 0.0002 0.82 ± 0.05 0.0230 1.3 3085.86 0.0216 ± 0.0003 0.93 ± 0.07 0.0222 2.7 3085.89 0.0179 ± 0.0004 1.05 ± 0.2 0.0183 2.2 3086.03 0.0196 ± 0.0005 0.93 ± 0.2 0.0202 3.0 3086.07 0.0230 ± 0.0003 1.00 ± 0.05 0.0242 5.0 3086.08 0.0299 ± 0.0005 0.71 ± 0.2 0.0299 0 Rel. Dif (%) Position (cm 1 ) ζ air (T ref ) (1/atm) This work n ζ ζ air (295K) (1/atm) Pine Rel. Dif (%) 3085.83 0.173 ± 0.02 1.06 ± 0.2 0.171 +1.2 3085.86 0.578 ± 0.002 1.14 ± 0.1 0.579 0.2 3085.89 0.521 ± 0.003 1.28 ±0.1 0.516 +1.0 3086.03 0.168 ± 0.05 1.51 ±0.25 0.176 4.5 3086.07 0.0698 ± 0.02 0.83 ±0.1 0.063 +10.8 3086.08 XX XX 0 XX 16
1.004 1.002 Kiruna (Sweden) 2011, Altitude 19.6 km 1 Transmission 0.998 0.996 0.994 0.992 0.99 0.988 3085.75 3085.8 3085.85 3085.9 3085.95 3086 3086.05 3086.1 3086.15 3086.2 2 x 10-3 Wavenumber (cm -1 ) 0-2 3085.75 3085.8 3085.85 3085.9 3085.95 3086 3086.05 3086.1 3086.15 3086.2 Application on in-situ measurements With HITRAN values : ρ CH4 = 1.49 ppmv With new parameters : ρ CH4 = 1.41 ppmv Differences of 5% M. Ghysels et al, ASA/HITRAN 2012 17
Predominant line-mixing at high pressures Conclusions Residuals of the same order of magnitude for LM and Hard-LM at high pressures Line-mixing also at low pressures Comparison at ambient temperature with Pine values [Pine, 1996] : good agreement Perspectives Process balloon spectra including new parameters (ongoing) M. Ghysels et al, ASA/HITRAN 2012 18
Equipe PicoSDLA: Scientific supervisor: Georges Durry (GSMA) GSMA, Université de Reims : Mélanie Ghysels, Julien Cousin, Laura Gomez-Martin Division technique de l'insu (Paris, CNRS) : Nadir Amarouche, Fabien Frérot, Jean-Christophe Samaké, Christophe Berthod, Louis Rey-Grange M. Ghysels et al, ASA/HITRAN 2012 19