Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 6 6 2006 10.5194/acpd-6-13307-2006 http://www.atmos-chem-phys-discuss.net/6/13307/2006/ http://www.atmos-chem-phys-discuss.net/6/13307/2006/acpd-6-13307-2006.html http://www.atmos-chem-phys-discuss.net/6/13307/2006/acpd-6-13307-2006.pdf 13307 13321 2006-12-18 Technical Note: Regularization performances with the error consistency method in the case of retrieved atmospheric profiles S. Ceccherini s.ceccherini@ifac.cnr.it C. Belotti B. Carli P. Raspollini M. Ridolfi Istituto di Fisica Applicata "Nello Carrara" del Consiglio Nazionale delle Ricerche, Via Madonna del Piano, 10 – 50019 Sesto Fiorentino, Italy Dipartimento di Chimica Fisica e Inorganica, Università di Bologna, Viale del Risorgimento, 4 – 40136 Bologna, Italy The retrieval of concentration vertical profiles of atmospheric constituents from spectroscopic measurements is often an ill-conditioned problem and regularization methods are frequently used to improve its stability. Recently a new method, that provides a good compromise between precision and vertical resolution, was proposed to determine analytically the value of the regularization parameter. This method is applied for the first time to real measurements with its implementation in the operational retrieval code of the satellite limb-emission measurements of the MIPAS instrument and its performances are quantitatively analyzed. The adopted regularization improves the stability of the retrieval providing smooth profiles without major degradation of the vertical resolution. In the analyzed measurements the retrieval procedure provides a vertical resolution that, in the troposphere and low stratosphere, is smaller than the vertical field of view of the instrument. Ceccherini, S.: Analytical determination of the regularization parameter in the retrieval of atmospheric vertical profiles, Opt. Lett., 30, 2554–2556, 2005. Doicu, A., Schreier, F., and Hess, M.: Iteratively regularized Gauss-Newton method for atmospheric remote sounding, Comput. Phys. Commun., 148, 214–226, 2002. Fischer, H., Blom, C., Oelhaf, H., Carli, B., Carlotti, M., Delbouille, L., Ehhalt, D., Flaud, J.-M., Isaksen, I., Lopez-Puertas, M., McElroy, C. T., and Zander, R.: SP-1229 Envisat – MIPAS, ESA Publications Division, Noordwijk The Netherlands, 2000. Levenberg, K.: A method for the solution of certain problems in least squares, Quart. Appl. Math., 2, 164–168, 1944. Marquardt, D. W.: An algorithm for the least-squares estimation of nonlinear parameters, SIAM J. Appl. Math., 11, 431–441, 1963. Raspollini, P., Belotti, C., Burgess, A., Carli, B., Carlotti, M., Ceccherini, S., Dinelli, B. M., Dudhia, A., Flaud, J.-M, Funke, B., Höpfner, M., Lopez-Puertas, M., Payne, V., Piccolo, C., Remedios, J. J., Ridolfi, M., and Spang, R.: MIPAS level 2 operational analysis, Atmos. Chem. Phys. Discuss., 6, 6525–6585, 2006. Ridolfi, M., Carli, B., Carlotti, M., von Clarmann, T., Dinelli, B. M., Dudhia, A., Flaud, J.-M., Höpfner, M., Morris, P. E., Raspollini, P., Stiller, G., and Wells, R. J.: Optimized forward model and retrieval scheme for MIPAS near-real-time data processing, Appl. Opt., 39, 1323–1340, 2000. Rodgers, C. D.: Inverse Methods for Atmospheric Sounding: Theory and Practice, Series on Atmospheric, Oceanic and Planetary Physics – Vol. 2, World Scientific, Singapore, 2000. Schimpf, B. and Schreier, F.: Robust and efficient inversion of vertical sounding atmospheric high-resolution spectra by means of regularization, J. Geophys. Res., 102(D13), 16 037–16 055, 1997. Steck, T.: Methods for determining regularization for atmospheric retrieval problems, Appl. Opt., 41, 1788–1797, 2002. Tikhonov, A.: On the solution of incorrectly stated problems and a method of regularization, Dokl. Acad. Nauk SSSR, 151, 501–504, 1963. Twomey, S.: Introduction to the mathematics of inversion in remote sensing and indirect measurements, Developments in Geomathematics 3, Elsevier Scientific Publishing Company, New York, 1977.