1. Laboratory spectroscopy at DLR Manfred Birk, Georg Wagner, Joep Loos German Aerospace Center (DLR) > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 1

2. Group established in 1990 Emphasis on quantitative spectroscopy of atmospheric trace gases Support of atmospheric remote sensing Initial focus on far infrared Soon extended to mid and near infrared; extended to UV in 2010 Participation in several EU-, ESA- and nationally-funded projects Member of HITRAN scientific advisory committee Background > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 2

3. Bruker IFS 120HR Fourier-transform spectrometer Replaced by new Bruker IFS 125HR in August 2010, extension to UV (250 nm) Coolable (190 K), heatable (950 K) cells, 170 m multireflection cell Lab equipment for production/handling of stable/unstable species Infrastructure > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 3

4. 20 cm absorption path Path length accuracy 0.1 % - requires raytracing! Coolable to 190 K High temperature homogeneity (0.1 K) Two window pairs allowing UV+MIR, MIR+FIR, UV+FIR New short absorption path cell > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 4

5. Designed at DLR in 1991, refurbished in 2012 80 cm baselength, up to 170 m absorption path Coolable to 190 K Equipped for flow experiments with unstable species Multireflection cell > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 5

6. Adaptable detector FOV to reduce background photon noise Coolable optical filter Photoconductive MCT with 700 cm -1 cut-on @ 45 K Improved detector design for thermal IR > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 6 Intercomparison standard Bruker MCT – DLR design Optical band pass filter, varying central wavenumber Detector @ 45 K 200 cm filter bandwidth 1 mm and 2 mm Bruker entrance aperture No absorber- and 90% absorption-setup

7. New IDL multispectrum fitting tool > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 7 Line models Voigt Speed-dependent Voigt (C. Boone) Speed-dependent Galatry + LM (F. Hase) pCqSDHC + LM (Ngo, Tran) Versatile interactive mode Choice of line model, fitparameters ILS, calibration factors, baseline, channelling, … Automatic mode Microwindow-, spectra-, fitparameter selection (Voigt) Goodness-of-fit Residua analysis (planned) Identification/prevention of correlation between fitted parameters Filecuts (results of single-spectra-fits vs. ms-fit) Identification of systematic spectrum-specific errors

8. New IDL multispectrum fitting tool > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 8

9. > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 9 Spectroscopic database work at DLR speciesFIRMIRNIRpurpose/applicationremark O3O3 S,  (T) , S,  (T),  (T, p) database improvement ClONO 2  (T, p) database improvement, MIPASdifficult synthesis N2O5N2O5  (T, p) database improvement, MIPAS OH/HO 2  new lethodologyextremely unstable BrO ,  (T) database improvement, MASTER/SOPRANOextremely unstable ClO ,  (T) , S database improvement, MASTER/SOPRANOunstable ClOOCl  (T, p) remote sensing, MIPASsample preparation difficult HOCl  FIR database CO S,  (T) error characterisation, high temperature database, Q/A <1% radiometric accuracy CO 2  (T, p) high temperature database H2OH2O , S,  (T) , S,  (T),  2 high temperature database improvement, climate, MIPAS, IASI, WALES sample preparation difficult NO , S,  (T) high temperature database, engine emissions NO 2  (T, p) high temperature database, engine emissions BrONO 2  (T, p) stratospheric Br budget and -chemistry sample preparation very difficult N2ON2O , S, ,  2, , LM Test of multispectrum fitting code CH 4 , S, ,  2, , LM NDACC (Network for the Detection of Atmospheric Composition Change)

10. N 2 O: line mixing in 3 rovibrational band > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 10

11. H 2 O: Linestrength intercomparison in 1 µm region > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 11 NIST:cavitiy ringdown by Joseph T. Hodges HIT:HITRAN 2008, mainly experimental data by Robert A. Toth Excellent agreement DLR-NIST, mostly < 1 % HITRAN2008 shows bias and large scatter

12. H 2 O: Linestrength intercomparison in 1 µm region > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 12 Lodi: ab initio calculations Good agreement for 2 0 1  0 0 0 and 0 0 3  0 0 0 with occasional outliers Entire subbands shifted: 1 2 1  0 0 0, 3 0 0  0 0 0, 1 0 2  0 0 0 up to 8 % Average differences 1 2 1  0 0 0 4.1% 2 0 1  0 0 0 0.0% 3 0 0  0 0 0 4.0% 1 0 2  0 0 0 -7.6% 0 0 3  0 0 0 -0.1%

13. Red: residuals DLR, pink: residuals HITRAN 2008 H 2 O: IASI retrieval improvements in H 2 O 2 region using DLR linestrength and pressure broadening parameters > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 13 Plots provided by S.A. Clough

14. BrONO 2 : New absorption cross sections > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 14 Q-branch peak intensity increases by 50 % from 296 K to 203 K Cross sections measured with 0.025 cm -1 resolution High resolution measurements @0.0017 cm -1 recorded at 296 K and 223 K, showing resolved features

15. Summary and current work > 2014 GEISA Workshop > J. Loos Laboratory spectroscopy at DLR > 03.06.2014DLR.de Chart 15 Laboratory equipment for measurements of stable and unstable species from FIR to UV at atmospheric pressures and temperatures Data reduction software including various quality assessment procedures Emphasis on defined error bars DFG-project H 2 O & CH 4 in 1750-4000 cm -1 spectral range Application in ground based solar occultation atmospheric measurements ESA-project: SEOM-Improved Atmospheric Spectroscopic Databases (IAS) TROPOMI on Sentinel-5 Precursor Improve CH 4, H 2 O, CO in the 2.3 µm region Resolve discrepancy of O 3 in the UV/10 µm regions Improve SO 2 in the UV