ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-7-9283-2007 Optical and geometrical characteristics of cirrus clouds over a mid-latitude lidar station Giannakaki E. 1 Balis D. S. 1 Amiridis V. 2 Kazadzis S. 1 Laboratory of Atmospheric Physics, Thessaloniki, Greece Institute for Space Applications and Remote Sensing, Athens, Greece 02 07 2007 7 4 9283 9317 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/7/9283/2007/acpd-7-9283-2007.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/7/9283/2007/acpd-7-9283-2007.pdf

Optical and geometrical characteristics of cirrus clouds over Thessaloniki, Greece (40.6°, 22.9°) have been determined from the analysis of lidar and radiosonde measurements performed during the period from 2000 to 2006. Cirrus clouds are generally observed in a mid altitude region ranging from 7 to 12 km, with mid-cloud temperatures in the range from –65° to –25°C. A seasonality of cirrus geometrical and temperature properties is found. The cloud thickness ranges from 0.85 to 5 km and 37% of our cases have thickness between 2 and 3 km. The retrieval of cloud's optical depth and lidar ratio is performed using three different methods, taking into account multiple scattering effects. The mean optical depth is found to be 0.3±0.24 and the corresponding mean lidar ratio is 28±17 sr. Sub-visual, thin and opaque cirrus clouds are observed at 7.5%, 51% and 42.5% of the measured cases respectively. The multiple scattering errors of the measured effective extinction coefficients range from 20% to 60% depending on cloud optical depth. A comparison of the results between the three methods shows good agreement. In addition we present the advantages and limitations of each method applied. The temperature and thickness dependencies on optical properties have also been studied in detail. A maximum mid-cloud depth of ~3 km is found at temperatures around ~–45°C while there is an indication that optical depth increases with increasing thickness and mid-cloud temperature. No clear dependence of the lidar ratio values on the cloud temperature and thickness was found.

 References Amiridis, V., Balis, D. S., Kazadzis, S., Bais, A., Giannakaki, E., Papayannis A., and Zerefos, C: Four-year aerosol observation with a Raman lidar at Thessaloniki, Greece, in the framework of EARLINET, J. Geophys. Res., 110, D21203, doi:10.1029/2005JD006190, 2005. 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, 1992. Balis D. S., Amiridis, V., Zerefos., C., Gerasopoulos, E., Andreae, M., Zanis, P., Kazantzidis, A., Kazadzis, S., and Papayannis, A.: Raman lidar and sunphotometric measurements of aerosol optical properties over Thessaloniki, Greece during a biomass burning episode, Atmos. Environ., 37, 4529–4538, 2003. Barrett, E. W. and Ben-Dov, O.: Application of the lidar to air pollution measurements, J. Appl. Meteorol., 6, 500–515, 1967. Cadet, B., Goldfarb, L., Faduilhe, D., Baldy, D., Giraud, V., Keckhut, P., and Rechou, A.: A sub-tropical cirrus clouds climatology from Reunion island (21° S, 55° E) lidar data set, Geophys. Res. Lett., 30(3), 1130, doi:10.1029/2002GL016342, 2003. Chen W. N., Chiang, C. W., and Nee, J. B.: Lidar ratio and depolarization ratio for cirrus clouds, Appl. Opt., 41, 6470–6476, 2002. Comstock, J. M. and Ackerman, T.: Ground-based lidar and radar remote sensing of tropical cirrus clouds at Nauru island: Cloud statistics and radiative impacts, J. Geophys. Res., 107(23), 4714, doi:10.1029/2002JD002203, 2002. Davis, P. A.: The analysis of lidar signatures of cirrus clouds, Appl. Opt., 8, 2099–2102, 1969. Eleftheratos K., Zerefos, C., Zanis, P., Balis, D. S., Tselioudis, G., Gierens, K., and Sausen, R.: A twenty-year study on natural and manmade global interannual fluctuations of cirrus cloud cover, Atmos. Chem. Phys., 7, 93–126, 2007. Eloranta, E.: Practical model for the calculation of multiply scatterd LIDAR returns, Appl. Opt., 37, 2464–2472, 1998. Fahey, D. W. and Schumann, U.: Aviation-Produced Aerosols and Cloudiness, Chapters 3 in Aviation and Global Atmosphere, A Special Report of IPCC (Intergovernmental Panel on Climate Change), J. E. Penner, D. H. Griggs, D. J. Dokken, M. McFarland, Cambridge University Press, Cambridge, UK, 65–120, 1999. Fernald, F. G., Herman, B. M., and Reagon, J. A.: Determination of aerosol height distributions by lidar, J. Appl. Meteorol., 11, 482–489, 1972. Fernald, F. G.: Analysis of atmospheric lidar observations; some comments, Appl. Opt., 23, 652–653, 1984. Fu, Q., and Liou, K. N.: Parameterization of the Radiative Properties of Cirrus Clouds, J. Atmos. Sci., 50, 2008-2025, 1993. Goldfarb L., Keckhut, P., Chanin, M.-L., and Hauchecorne, A.: Cirrus climatological results from lidar measurements at OHP (44° N, 6° E), Geophys. Res. Lett., 28, 1967–1690, 2001. Heymsfield, A. J. and Platt, C. M. R.: A parameterization of the particle size spectrum of ice clouds in terms of the ambient temperature and the ice water content, J. Atmos. Sci., 41, 84-6-855, 1984. Hogan, R.: Fast approximate calculation of multiply scattered lidar returns, Appl. Opt., 45, 5984–5992, 2006. Klett, J. D.: Stable analytical inversion solution for processing lidar returns, Appl. Opt., 20, 211–220, 1981. Krishna Murthy, B. V., Parameswaran, K., and Rose, K. O.: Temporal variations of the tropical tropopause characteristics, J. Atmos. Sci., 43, 914–922, 1986. Mace, G. G., Clothiaux, E. E., and Ackerman, T. P.: The composite characteristics of cirrus clouds: Bulk properties revealed by one year continues cloud radar data, J. Climate, 14, 2185–2203, 2001. Matthias, V., Bosenberg, J., Freudenthaler, V., Amodeo, A., Balin, I., and Balis, D.: Aerosol lidar intercomparison in the framework of EARLINET project: 1. Instruments, Appl. Opt., 43, 961–976, 2004 Platt, C. M. R.: Lidar and radiometric observations of cirrus clouds, J. Atmos. Sci., 30, 1191–1204, 1973. Platt, C. M. R.: Remote sounding of high clouds. I: Of visible and infrared optical properties from lidar and radiometer measurements, J. Appl. Meteorol., 18, 1130–1143, 1979. Platt, C. M. R., Scott, J. C., and Dilley, C.: Remote sounding of high clouds. Part VI: Optical properties, J. Atmos. Sci., 44, 729–747, 1987. Platt, C. M. R. and Harshvardhan: Temperature dependencies of cirrus extinction: implications for climate feedback, J. Geophys. Res., 93, 11 051-11 058, 1988. Platt, C. M. R., Young, S. A., Carswell, A. I., Pal, S. R., McCormick, M. P., Winker, D. M., DelGuasta, M., Stefanutti, L., Eberhard, W. L., Hardesty, M., Flamant, P. H., Valentin, R., Forgan, B., Gimmestad, G. G., Jager, H., Khmelevtsov, S., Kovel, I., Kaprieolev, B., Lu, Da-ren, Sassen, K., Shamanaev, V. S., Uchino, O., Mizuno, Y., Wandinger, U., Weitkamp, C., Ansmann, A., and Wooldridge, C.: The experimental cloud lidar pilot study (ECLIPS) for cloud-radiation research, Bull. Am. Meteorol. Soc., 75, 1635–1654, 1994. Sassen, K. and Cho, B.Y.: Subvisual-thin cirrus lidar dataset for satellite verification and climatological research, J. Appl. Meterorol., 31, 1275–1285, 1992. Sassen, K. and Campbell, J. R.: A midlatitude cirrus cloud climatology from the facility for atmospheric remote sensing, part I: Macrophysical and synoptic properties, J. Atmos. Sci., 58, 481–496, 2001. Sassen K. and Comstock, J.: A midlatitude cirrus cloud climatology from the facility for atmospheric remote sensing. Part III: Radiative properties, J. Atmos. Sci., 58, 2113–2127, 2001. % %Seifert, P., Ansmann, A., Muller, D., Wandinger, U., and Althausen D.: %Cirrus observations with Lidar, Radiosonde, and Satellite over the Tropical %Indian Ocean During Northeast and Southwest Monsoon Seasons, J. Geophys. %Res., in review\blackbox\bf status?, 2007. Stephens, G. L. and Webster, P.J.: Clouds and Climate: Sensitivity of Simple Systems, J. Atmos. Sci., 38, 235–247, 1981. Sunilkumar, S. V. and Parameswaran, K.: Temperature dependence of tropical cirrus properties and radiative effects, J. Geophys. Res., 110, D13205, doi:10.1029/2004JD005426, 2005. Viezee, W., Uthe, E. E., and Collis, R. T. H.: Lidar observations of airfield approach conditions, J. Appl. Meteorol., 8, 274–283, 1969. Wandinger, U.: Multiple-scattering influence on extinction-and backscatter-coefficient measurements with Raman and high-spectral-resolution lidars, Appl. Opt., 37, 417–427, 1998. Wang, P., Minnis, P., McCormick, M. P., Kent, G. S., and Skeens, K. M.: A 6-year climatology of cloud occurrences frequency from Stratospheric Aerosol and Gas Experiment II observations (1985–1990), J. Geophys. Res., 101, 29 407–29 429, 1996. Wang, P., Minnis, P., McCormick, M. P., Kent, G. S., Yue, G. K., Young, D. F., and Skeens, K. M.: A study of the vertical structure of tropical (20° S–20° N) optically thin clouds from SAGE II observations, Atmos. Res., 47–48, 599–614, 1998. Wang, Z. and Sassen, K.: Cirrus cloud microphysical property retrieval using lidar and radar measurements. Part II: Midlatitude cirrus microphysical and radiative properties, J. Atmos. Sci., 59, 2291–2302, 2002. Wang X., Boselli, A., Avino, L. D., Velotta, R., Spinelli, N., Bruscaglioni, P., Ismaelli, A., and Zaccanti, G.: An algorithm to determine cirrus properties from analysis of multiple-scattering influence on lidar signals, Appl. Phys. B, 80, 609–615, 2005. Young S.: Analysis of lidar backscatter profiles in optically thin cirrus, Appl. Opt., 34, 7019–7031, 1995. Zerefos C. S., Eleftheratos, K., Balis, D. S., Zanis, P., Tselioudis, G., and Meleti, C.: Evidence of impact of aviation on cirrus cloud formation, Atmos. Chem. Phys., 3, 1633–1644, 2003.