Atmospheric Chemistry and Physics Discussions
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2008
10.5194/acpd-8-8913-2008
http://www.atmos-chem-phys-discuss.net/8/8913/2008/
http://www.atmos-chem-phys-discuss.net/8/8913/2008/acpd-8-8913-2008.html
http://www.atmos-chem-phys-discuss.net/8/8913/2008/acpd-8-8913-2008.pdf
8913
8949
2008-05-20
Statistical estimation of stratospheric particle size distribution by combining optical modelling and lidar scattering measurements
J. Jumelet
julien.jumelet@aero.jussieu.fr
S. Bekki
C. David
P. Keckhut
Service d'Aéronomie du CNRS/IPSL, UPMC Paris 6, Paris, France
A method for estimating the stratospheric particle size distribution from
multiwavelength lidar measurements is presented. It is based on matching
measured and model-simulated backscatter coefficients. The lidar backscatter
coefficients measured at the three commonly used wavelengths 355, 532 and
1064 nm are compared to a precomputed look-up table of model-calculated
values. The optical model assumes that particles are spherical and that
their size distribution is unimodal. This inverse problem is not trivial
because the optical model is highly non-linear with a strong sensitivity to
the size distribution parameters in some cases. The errors in the lidar
backscatter coefficients are explicitly taken into account in the
estimation. The method takes advantage of the statistical properties of the
possible solution cluster to identify the most probable size distribution
parameters. In order to discard model-simulated outliers resulting from the
strong non-linearity of the model, a 1σ-filter is applied to the
solution cluster. Within the filtered solution cluster, the estimation
algorithm minimizes a cost function of the misfit between measurements and
model simulations.
<br><br>
Two validation cases are presented on Polar Stratospheric Cloud (PSC) events
detected above the ALOMAR observatory (69° N – Norway). A first
validation is performed against optical particle counter measurements
carried out in January 1996. In non-depolarizing regions of the cloud (i.e.
spherical particles), the parameters of an unimodal size distribution and
those of the optically dominant mode of a bimodal size distribution are
quite successfully retrieved, especially for the mode radius and the
geometrical standard deviation. As expected, the algorithm performs poorly
when solid particles drive the backscatter coefficient. A small bias is
identified in modelling the refractive index when compared to previous works
that inferred PSC type Ib refractive indices. The accuracy of the size
distribution retrieval is improved when the refractive index is set to the
value inferred in the reference paper.
<br><br>
Our results are then compared to values retrieved with another similar
method that does not account for the effect of the measurements errors and
the non-linearity of the optical model on the likelihood of the solution.
The case considered is a liquid PSC observed over northern Scandinavia on
January, 2005. An excellent agreement is found between the two methods when
our algorithm is applied without any statistical filtering of the solution
cluster. However, the solution for the geometrical standard deviation
appears to be rather unlikely with a value close to unity (σ≈1.04). When our algorithm is applied with solution filtering, a more
realistic value of the standard deviation (σ≈1.27) is
found. This highlights the importance of taking into account the non
linearity of the model together with the lidar errors, when estimating
particle size distribution parameters from lidar measurements.
Ansmann, A., Riebesell, M., and Weitkamp, C.: Measurement of atmospheric aerosol extinction profiles with a Raman lidar, Opt. Lett., 15, 746–748, 1990.
Ansmann, A., Riebesell, M., Wandinger, U., Weitkamp, C., Voss, E., Lahmann, W., and Michaelis, W.: Combined Raman elastic-backscatter lidar for vertical profiling of moisture, aerosol extinction, backscatter, and lidar ratio, Appl. Phys. B, 55, 18–28, 1992a.
Ansmann, A., Wandinger, U., Riebesell, M., Weitkamp, C., and Michaelis, W.: Independent measurement of extinction and backscatter profiles in cirrus clouds by using a combined Raman elastic-backscatter lidar, Appl. Opt., 31, 7113–7131, 1992b.
Assessment of Stratospheric Aerosol Properties (ASAP), WCRP-124, WMO/TD-No. 1295, SPARC Report No 4, 2006.
Baumgarten, G., Fiedler, J., and Von Cossart, G.: The size of noctilucent cloud particles above ALOMAR (69N, 16E): Optical modelling and method description, J. Adv. Space Res., 40, 772–784, doi:10.1016/j.asr.2007.01.018, 2007.
Beyerle, A., Neuber, R., and Schrems, O.: Multiwavelengths lidar measurements of stratospheric aerosols above Spitzenberg during winter 1992/1993, Geophys. Res. Lett., 21, 57–60, 1994.
Blum, U., Khosrawi, F., Baumgarten, G., Stebel, K., Müller, R., and Fricke, K. H.: Simultaneous lidar observations of a polar stratospheric cloud on the east and west sides of the scandinavian mountains and microphysical box model calculations, Ann. Geophys., 24, 3267–3277, 2006.
Bohren, C. F. and Huffman, D. R.: Absorption and Scattering of Light by Small Particles, J. Wiley & Sons, New York, 530 pp., 1983.
Carslaw, K. S., Peter, T., and Clegg, S. L.: Modelling the composition of liquid stratospheric aerosols, Rev. Geophys., 35, 125–154, 1997.
Charlson, R. J. and Heintzenberg, J.: Aerosol Forcing of Climate, Wiley, Chichester, 1995.
Cooney, J. and Pina, M.: Laser radar measurements of atmospheric temperature profiles by use of Raman rotational backscatter, Appl. Opt., 15, 602–603, 1976.
David, C., Godin, S., Mégie, G., Emery, Y., and Flésia, C.: Physical state and composition of Polar Stratospheric Clouds inferred from airborne lidar measurements during SESAME, J. Atmos. Chem., 27, 1–16, 1997.
Deshler, T., Nardi, B., Adriani, A., Cairo, F., Hansen, G., Fierli, F., Hauchecorne, A., and Pulvirenti, L.: Determining the index of refraction of polar stratospheric clouds above Andoya (69° N) by combing size-resolved concentration and optical scattering measurements, J. Geophys. Res., 105(D3), 3943–3953, 2000.
Deshler, T., Hervig, M. E., Hofmann, D. J., Rosen, J. M., and Liley, J. B.: Thirty years of in situ stratospheric aerosol size distribution measurements from Laramie, Wyoming (41° N), using balloon-borne instruments, J. Geophys. Res., 108(D5), 4167, doi:10.1029/2002JD002514, 2003.
Elbern, H. and Schmidt, H.: Ozone episode analysis by four-dimensional variational chemistry data assimilation, J. Geophys. Res., 106(D4), 3569–3590, 2001.
Fiocco G. and Smullins, L. D.: Detection of scattering layers in the upper atmosphere (60–140 km) by optical radar, Nature, 199, 1275–1276, doi:10.1038/1991275a0, 1963.
Hanson, G. and Hoppe, U. P.: Lidar observations of polar stratospheric clouds and stratospheric temperature in winter 1995/96 over northern Norway, Geophys. Res. Lett., 24(2), 131–134, 1997.
Hofmann, D. J. and Rosen, J. M.: Stratospheric sulphuric acid layer: Evidence for an anthropogenic component, Science, 208, 1368–1370, 1980.
Hofmann, D. J.: Increase in the stratospheric background sulphuric acid aerosol mass in the past 10 years, Science, 248, 996–1000, 1990.
Junge, C. E., Chagnon, C. W., and Manson, J. E.: Stratospheric aerosols, J. Meteorol., 18, 81–108, 1961.
Klett, J. D.: Stable analytical inversion solution for processing lidar returns, Appl. Opt., 20, 211–220, 1981.
Klett, J. D.: Lidar inversion with variable backscatter/extinction ratios, Appl. Opt., 24, 1638–1643, 1985.
Krieger, U. K., Mössinger, J. C. , Luo, B., Weers, U., and Peters, T.: Measurements of the refractive indices of H<sub>2</sub>SO<sub>4</sub>/HNO<sub>3</sub>/H<sub>2</sub>0 solutions to stratospheric temperatures, Appl. Opt., 39(21), 3691–3703, 2000.
Lahoz, W. A., Geer, A.J., Bekki, S., Bormann, N., Ceccherini, S., Elbern, H., Errera, Q., Eskes, H. J., Fonteyn, D., Jackson, D. R., Khattatov, B., Marchand, M., Massart, S., Peuch, V. H., Rharmili, S., Ridolfi, M., Segers, A., Talagrand, O., Thornton, H. E., Vik, A. F., and von Clarmann, T.: The Assimilation of Envisat data (ASSET) project, Atmos. Chem. Phys., 7, 1773–1796, 2007.
Larsen, N.: Polar stratospheric clouds Microphysical and optical models, Danish Meteorological Institute, scientific report, 00–06, 85 pp., 2000.
Luo, B., Krieger, U. K., and Peter, T.: Densities and refractive indicies of H<sub>2</sub>SO<sub>4</sub>/HNO<sub>3</sub>/H<sub>2</sub>O solutions to stratospheric temperatures, Geophys. Res. Lett., 23, 3707–3710, 1996.
McCormick, M. P., Hamill, P., Pepin, T. J., Chu, W. P., Swissler, T. J., and McMaster, L. R.: Satellite studies of the stratospheric aerosol, B. Am. Meteorol. Soc., 60, 1038–1046, 1979.
Mehrtens, H., von Zahn, U., Fierli, F., Nardi, N., and Deshler, T.: Type I PSC-particle properties, measurements at ALOMAR from 1995 to 1997, Geophys. Res. Lett., 26(D5), 603–606, 1999.
Mishchenko, M. I. and Travis, L. D.: Capabilities and limitations of a current FORTRAN implementation of the T-matrix method for randomly oriented rotationally symmetric scatterers, J. Quant. Spectrosc. Ra., 60, 309–324, 1998.
Müller, H. and Quenzel, H.: Information content of multispectral lidar measurements with respect to the aerosol size distribution, Appl. Opt., 24, 648–654, 1985.
Müller, D., Wandinger, U., Althausen, D., Mattis, I., and Ansmann, A.: Retrieval of physical particle properties from lidar observations of extinction and backscatter at multiple wavelengths, Appl. Opt., 37, 2260–2263, 1998.
Müller, D., Wandinger, U., and Ansmann, A.: Microphysical particle parameters from extinction and backscatter lidar data by inversion with regularization: theory, Appl. Opt., 38, 2346–2357, 1999.
Müller, D., Wagner, F., Wandinger, U., Ansmann, A., Wendisch, M., Althausen, D., and von Hoyningen-Huene, W.: Microphysical particle parameters from extinction and backscatter lidar data by inversion with regularization: experiment, Appl. Opt., 39, 1879–1892, 2000.
Nedeljkovic, D., Hauchecorne, A., and Chanin, M. L.: Rotational Raman lidar to measure the atmospheric temperature from the ground to 30 km, IEEE Trans. Geosci. Remote Sensing, 31, 90–101, 1993.
Peter, T.: Microphysics and heterogeneous chemistry of polar stratospheric clouds, Annu. Rev. Phys. Chem., 48, 785–822, 1997.
Pinnick, R. G., Rosen, J. M., and Hofmann, D. J.: Stratospheric aerosol measurements III: Optical model calculations, J Atmos. Sci., 33, 304–314, 1976.
Robock, A.: Comment on "Climate forcing by the volcanic eruption of Mount Pinatubo" by David H. Douglass and Robert S. Knox, Geophys. Res. Lett., 32, L20711, doi:10.1029/2005GL023287, 2005.
Scarchilli, C., Adriani, A., Cairo, F., Di Donfrancesco, G., Buontempo, C., Snels, M., Moriconi, M. L., Deshler, T., Larsen, N., Luo, B., Mauersberger, K., Ovarlez, J., Rosen, J., and Schreiner, J.: Determination of polar stratospheric cloud particle refractive indices by use of in situ optical measurements and T-matrix calculations, Appl. Opt., 44, 3302–3311, 2005.
Tarantola, A.: Inverse Problem Theory: Methods for Data Fitting and Model Parameter Estimation, Elsevier, Amsterdam, 1987.
Tikhonov, A. N. and Arsenin, V. Y.: Solution of Ill-Posed Problems, Wiley, New York, 1977.
Veselovskii, I., Kolgotin, A., Griaznov, V., Müller, D., Wandinger, U., and Whiteman, D. N.: Inversion with regularization for the retrieval of tropospheric aerosol parameters from multiwavelength lidar sounding, Appl. Opt., 41, 3685–3699, 2002.
Veselovskii, I., A. Kolgotin, V. Griaznov, D. Müller, K. Franke, and Whiteman, D. N.: Inversion of multiwavelength Raman lidar data for retrieval of bimodal aerosol size distribution, Appl. Opt., 43, 1180–1195, 2004.
Veselovskii, I., Kolgotin, A., Müller, D., and Whiteman, D. N.: Information content of multiwavelength lidar data with respect to microphysical particle properties derived from eigenvalue analysis, Appl. Opt., 44(25), 5292–5303, 2005.
Vömel, H., Rummukainen, M., Kivi, R., Jarhu, J., Turunen, T., Kyrö, E., Rosen, J., Kjome, N., and Oltmans, S.: Dehydratation and sedimentation of ice particles in the Arctic stratospheric vortex, Geophys. Res. Lett., 24, 795–798, 1997.
Von Zahn, U. G., von Cossart, G., Fiedler, J., Fricke, K. H., Nelke, G., Baumgarten, G., Rees, D., Hauchecorne, A., and Adolfsen, K.: The ALOMAR Rayleigh/Mie/Raman lidar: objectives, configuration, and performance, Ann. Geophysicae, 18, 815–833, 2000.
WMO (World Meteorological Organization) Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project – Report No. 50, 572 pp., Geneva, 2007.