Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 7 13 2007 10.5194/acp-7-3537-2007 http://www.atmos-chem-phys.net/7/3537/2007/ http://www.atmos-chem-phys.net/7/3537/2007/acp-7-3537-2007.html http://www.atmos-chem-phys.net/7/3537/2007/acp-7-3537-2007.pdf 3537 3557 2007-07-06 Technical Note: Interference errors in infrared remote sounding of the atmosphere R. Sussmann ralf.sussmann@imk.fzk.de T. Borsdorff IMK-IFU, Forschungszentrum Karlsruhe, Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany Classical error analysis in remote sounding distinguishes between four classes: "smoothing errors," "model parameter errors," "forward model errors," and "retrieval noise errors". For infrared sounding "interference errors", which, in general, cannot be described by these four terms, can be significant. Interference errors originate from spectral residuals due to "interfering species" whose spectral features overlap with the signatures of the target species. A general method for quantification of interference errors is presented, which covers all possible algorithmic implementations, i.e., fine-grid retrievals of the interfering species or coarse-grid retrievals, and cases where the interfering species are not retrieved. In classical retrieval setups interference errors can exceed smoothing errors and can vary by orders of magnitude due to state dependency. An optimum strategy is suggested which practically eliminates interference errors by systematically minimizing the regularization strength applied to joint profile retrieval of the interfering species. This leads to an interfering-species selective deweighting of the retrieval. Details of microwindow selection are no longer critical for this optimum retrieval and widened microwindows even lead to reduced overall (smoothing and interference) errors. Since computational power will increase, more and more operational algorithms will be able to utilize this optimum strategy in the future. The findings of this paper can be applied to soundings of all infrared-active atmospheric species, which include more than two dozen different gases relevant to climate and ozone. This holds for all kinds of infrared remote sounding systems, i.e., retrievals from ground-based, balloon-borne, airborne, or satellite spectroradiometers. Bowman, K., Rodgers, C. D., Kulawik, S. S., Worden, J., Sarkissian, E., Ostermann, G., Steck, T., Lou, M., Eldering, A., Shephard, M., Worden, H., Lampel, M., Clough, S., Brown, P., Rinsland, C., Gunson, M., and Beer, R.: Tropospheric Emission Spectrometer: Retrieval Method and Error Analysis, IEEE Trans. Geosci. Remote Sens., 44, 1297–1307, 2006. Connor, B. J., Parrish, A., Tsou, J.-J., and McCormick, M. P.: Error analysis for the ground-based microwave ozone measurements during STOIC, J. Geophys. Res., 100, 9283–9291, 1995. Deeter, M. N., Emmons, L. K., Francis, G. L., Edwards, D. P., Gille, J. C., Warner, J. X., Khattatov, B., Ziskin, D., Lamarque, J.-F., Ho, S.-P., Yuding, V., Attie, J.-L. Packman, D., Chen, J., Mao, D., and Drummond, J. R.: Operational carbon monoxide retrieval algorithm and selected results for the MOPITT instrument, J. Geophys.Res., 108, 4399–4409, 2003. Dudhia, A., Jay, V. L., and Rodgers, C. D.: Microwindow selection for high-spectral-resolution sounders, Appl. Opt., 41, 3665–3673, 2002. Echle, G., von Clarmann, T., Dudhia, A., Flaud, J.-M., Funke, B., Glatthor, N., Kerrridge, B., López-Puertas, M., Martín-Torres, F. J., and Stiller, G.: Optimized spectral microwindows for data analysis of the Michelson Interferometer for Passive Atmospheric Sounding on the Environmental Satellite, Appl. Opt., 39, 5531–5540, 2000. Jones, N. B., Rinsland, C. P., Liley, J. B., and Rosen, J.: Correlation of aerosol and carbon monoxide at 45° S: Evidence of biomass burning emissions, Geophys. Res. Lett., 28, 709–712, 2001. Paton-Walsh, C., Jones, N. B., Wilson, S. R., Haverd, V., Meier, A., Griffith, D. W. T., and Rinsland, C. P.: Measurements of trace gas emissions from Australian forest fires and correlations with coincident measurements of aerosol optical depth, J. Geophys. Res., 110, D24305, 2005, doi:10.1029/2005JD006202. Pougatchev, N. S. and Rinsland, C. P.: Spectroscopic study of the seasonal variation of carbon monoxide vertical distribution above Kitt Peak, J. Geophys. Res., 100, 1409–1416, 1995. Pougatchev, N. S., Jones, N. B., Connor, B. J., Rinsland, C. P., Becker, E., Coffey, M. T., Connors, V. S., Demoulin, P., Dzhola, A. V., Fast, H., Grechko, E. I., Hannigan, J. W., Koike, M., Kondo, Y., Mahieu, E., Mankin, W. G., Mittermeier, R. L., Notholt, J., Reichle Jr., H. G., Sen, B., Steele, L. P., Toon, G. C., Yurganov, L. N., Zander, R., and Zhao, Y.: Ground-based infrared solar spectroscopic measurements of carbon monoxide during 1994 Measurement of Air Pollution from Space flights, J. Geophys. Res., 103(D15), 19 317–19 325, 1998. Rinsland, C. P., Jones, N. B., Connor, B. J., Logan, J. A., Pougatchev, N. S., Goldman, A., Murcray, F. J., Stephen, T. M., Pine, A. S., Zander, R., Mahieu, E., and Demoulin, P.: Northern and southern hemisphere ground-based infrared spectroscopic measurements of tropospheric carbon monoxide and ethane, J. Geophys. Res., 103, 28 197–28 217, 1998. Rinsland, C. P., Mahieu, E., Zander, R., Demoulin, P., Forrer, J., and Buchmann, B.: Free tropospheric CO, C₂H$_6$, and HCN over central Europe: Recent measurements from the Jungfraujoch station including the detection of elevated columns during 1998, J. Geophys. Res., 105, 24 235–24 249, 2000. Rinsland, C. P., Jones, N. B., Connor, B. J., Wood, S. W., Goldman, A., Stephen, T. M., Murcray, F. J., Chiou, L. S., Zander, R., and Mahieu, E.: Multilayer infrared solar spectroscopic measurements of HCN, CO, C₂H$_6$, and C₂H₂ tropospheric columns above Lauder, New Zealand (45° S latitude), J. Geophys. Res., 107(D14), 4185, doi:10.1029/2001JD001150, 2002. Rodgers, C. D.: Retrieval of Atmospheric Temperature and Composition From Remote Measurements of Thermal Radiation, Rev. Geophys. Space Phys., 14, 609–624, 1976. Rodgers, C. D.: Characterization and Error Analysis of Profiles Retrieved From Remote Sounding Measurements, J. Geophys. Res., 95, 5587–5595, 1990. Rodgers, C. D.: Inverse Methods for Atmospheric Sounding: Theory and Practice, vol. 2 of Series on Atmospheric, Oceanic and Planetary Physics, edited by: Taylor, F. W., World Scientific, 2000. Rodgers, C. D. and Connor, B. J.: Intercomparison of remote sounding instruments, J. Geophys. Res., 108(D3), 4116, doi:10.1029/2002JD002299, 2003. Rothman, L. S., Jacquemart, D., Barbe, A., Benner, D. C., Birk, M., Brown, L. R., Carleer, M. R., Chackeria Jr., C., Chance, K., Coudert, L. H., Dana, V., Devi, V. M., Flaud, J.-M., Gamache, R. R., Goldman, A., Hartmann, J.-M., Jucks, K. W., Maki, A. G., Mandin, J.-Y., Massie, S. T., Orphal, J., Perrin, A., Rinsland, C. P., Smith, M. A. H., Tennyson, J., Tolchenov, R. N., Toth, R. A., Vander Auwera, J., Varanasi, P., and Wagner, G.: The HITRAN 2004 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transfer, 96, 139–204, 2005. Steck, T. and von Clarmann, T.: Constrained profile retrieval applied to the observation mode of the Michelson Interferometer for Passive Atmospheric Sounding, Appl. Opt., 40, 3559–3571, 2001. Steck, T.: Methods for determining regularization for atmospheric retrieval problems, Appl. Opt., 41, 1788–1797, 2002. Sussmann, R. and Schäfer, K.: Infrared spectroscopy of tropospheric trace gases: combined analysis of horizontal and vertical column abundances, Appl. Opt., 36, 735–741, 1997. Sussmann, R. and Buchwitz, M.: Initial validation of ENVISAT/SCIAMACHY columnar CO by FTIR profile retrievals at the Ground-Truthing Station Zugspitze, Atmos. Chem. Phys., 5, 1497–1503, 2005. Sussmann, R., Stremme, W., Buchwitz, M., and de Beek, R.: Validation of ENVISAT/SCIAMACHY columnar methane by solar FTIR spectrometry at the Ground-Truthing Station Zugspitze, Atmos. Chem. Phys., 5, 2419–2429, 2005a. Sussmann, R., Stremme, W., Burrows, J. P., Richter, A., Seiler, W., and Rettinger, M.: Stratospheric and tropospheric NO₂ variability on the diurnal and annual scale: a combined retrieval from ENVISAT/SCIAMACHY and solar FTIR at the Permanent Ground-Truthing Facility Zugspitze/Garmisch, Atmos. Chem. Phys., 5, 2657–2677, 2005b. Tikhonov, A.: On the solution of incorrectly stated problems and a method of regularization, Dokl. Acad. Nauk SSSR, 151, 501–504, 1963. Velazco, V., Notholt, J., Warneke, T., Lawrence, M., Bremer, H., Drummond, J., Schulz, A., Krieg, J., and Schrems, O.: Latitude and altitude variability of carbon monoxide in the Atlantic detected from ship-borne Fourier transform spectrometry, model, and satellite data, J. Geophys. Res., 110, D09306, doi:10.1029/2004JD005351, 2005. von Clarmann, T. and Echle, G.: Selection of optimized microwindows for atmospheric spectroscopy, Appl. Opt., 37, 7661–7669, 1998. Worden, J., Kulawik, S. S., Shephard, M. W., Clough, S. A., Worden, H., Bowman, K., and Goldman, A.: Predicted errors from tropospheric emission spectrometer nadir retrievals from spectral window selection, J. Geophys. Res., 109, D09308, doi:10.1029/2004JD00452, 2004. Yurganov, L. N., Blumenstock, T., Grechko, E. I., Hase, F., Hyer, E. J., Kasischke, E. S., Koike, M., Kondo, Y., Kramer, I., Leung, F.-Y., Mahieu, E., Mellqvist, J., Notholt, J., Novelli, P. C., Rinsland, C. P., Scheel, H. E., Schulz, A., Strandberg, A., Sussmann, R., Tanimoto, H., Velazco, V., Zander, R., and Zhao, Y.: A quantitative assessment of the 1998 carbon monoxide emission anomaly in the Northern Hemisphere based on total column and surface concentration measurements, J. Geophys. Res., 109, D15305, doi:10.1029/2004JD004559, 2004. Yurganov, L. N., Duchatelet, P., Dzhola, A. V., Edwards, D. P., Hase, F., Kramer, I., Mahieu, E., Mellqvist, J., Notholt, J., Novelli. P. C., Rockmann, A., Scheel, H. E., Schneider, M., Schulz, A., Strandberg, A., Sussmann, R., Tanimoto, H., Velazco, V., Drummond, J. R., and Gille, J. C.: Increased Northern Hemispheric carbon monoxide burden in the troposphere in 2002 and 2003 detected from the ground and from space, Atmos. Chem. Phys., 5, 563–573, 2005. Zhao, Y., Kondo, Y., Murcray, F. J., Liu, X., Koike, M., Kita, K., Nakajima, H., Murata, I., and Suzuki, K.: Carbon monoxide column abundances and tropospheric concentrations retrieved from high resolution ground-based infrared solar spectra at 43.5° N over Japan, J. Geophys. Res., 102(D19), 23 403–23 411, 1997.