References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-7-1415-2007

Extinction coefficients retrieved in deep tropical ice clouds from lidar observations using a CALIPSO-like algorithm compared to in-situ measurements from the cloud integrating nephelometer during CRYSTAL-FACE

Noel

¹ Winker

D. M.

² Garrett

T. J.

³ McGill

⁴

Laboratoire de Météorologie Dynamique, Palaiseau, France

NASA Langley Research Center, VA, USA

Univ. of Utah, UT, USA

NASA Goddard Space Flight Center, Greenbelt, ML, USA

08 03 2007

7 5 1415 1422

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This paper presents a comparison of lidar ratios and volume extinction coefficients in tropical ice clouds, retrieved using observations from two instruments: the 532-nm <it>Cloud Physics Lidar</it> (CPL), and the in-situ <it>Cloud Integrating Nephelometer</it> (CIN) probe. Both instruments were mounted on airborne platforms during the CRYSTAL-FACE campaign and took measurements up to 17 km. Coincident observations from two cases of ice clouds located on top of deep convective systems are compared. First, lidar ratios are retrieved from CPL observations of attenuated backscatter, using a retrieval algorithm for opaque cloud similar to one used in the recently launched CALIPSO mission, and compared to results from the regular CPL algorithm. These lidar ratios are used to retrieve extinction coefficient profiles, which are compared to actual observations from the CIN in-situ probe, putting the emphasis on their vertical variability. When observations coincide, retrievals from both instruments are very similar, in the limits of colocation. Differences are generally variations around the average profiles, and general trends on larger spatial scales are well reproduced. The two instruments agree well, with an average difference of less than 11% on optical depth retrievals. Results suggest the CALIPSO Deep Convection algorithm can be trusted to deliver realistic estimates of the lidar ratio, leading to good retrievals of extinction coefficients.

References 1

Chiriaco, M., Chepfer, H., Noel, V., Delaval, A., Haeffelin, M., Dubuisson, P., and Yang, P.: Improving Retrievals of Cirrus Cloud Particle Size Coupling Lidar and Three-channel Radiometric techniques, Monthly Weather Review, 132, 1684–1700, 2004.

Chiriaco M., Chepfer, H., Noel, V., Delaval, A., Haeffelin, M., Dubuisson, P. and Yang, P.: Improving Retrievals of Cirrus Cloud Particle Size Coupling Lidar and Three-channel Radiometric techniques, Monthly Weather Review, 132, 1684–1700, 2004.

Garrett T. J., Gerber, H., Baumgardner, D. G., Twohy, C. H., and Weinstock, E. M.: Small, highly reflective ice crystals in low-latitude cirrus, Geophys. Res. Lett., 30, doi:10.1029/2003GL018153, 2003.

Garrett T. J., Heymsfield, A. J., McGill, M. J., Ridley, B. A., Baumgardner, D. G., Bui, T. P., and Webster, C. R.: Convective generation of cirrus near the tropopause J. Geophys. Rev., 109, D21203, 2004.

Garrett T. J.: Comment on "Effective radius of ice cloud particle populations derived from aircraft probes" by Heymsfield et al (2006), J. Atmos. Ocean. Tech., accepted, 2007.

Gerber, H., Takano, Y., Garrett, T. J., and Hobbs, P. V.: Nephelometer measurements of the Asymmetry parameter, Volume extinction coefficient and Backscatter ratio in Artic clouds, J. Atmos. Sci., 57, 3021–3034, 2000.

Gerber, H.: Comment on "Effective radius of ice cloud particle populations derived from aircraft probes" by Heymsfield et al. (2006), J. Atmos. Ocean. Tech., accepted, 2007.

Hartmann, D. L., Ockert-Bell, M. E., and Michelsen, M. L.: The effect of cloud type on earth's energy balance : Global analysis, J. of Climate, 5 , 1281–1304, 1992.

Heymsfield, A. J. and McFarquhar, G. M.: On the high albedos of anvil cirrus in the tropical pacific warm pool: microphysical interpretations from CEPEX and from Kwajalein, Marshall Islands, J. Atmos. Sci., 53, 2401–2423, 1996.

Heymsfield A. J., C. Schmitt, A. Bansemer, G.-J. Van Zadelhoff, M. J. McGill, C. Twohy, D. Baumgardner, 2006: Effective Radius of Ice Cloud Particle Populations Derived from Aircraft Probes. J. Atmos. Ocean. Technol., 23, 361–380.

Jensen E. J., Starr, D., and Toon, O. B.: Mission investigates tropical cirrus clouds. EOS, 85, 45–50, 2004.

King, M. D., Platnick, S., Moeller, C. C., Revercomb, H. E., and Chu, D. A.: Remote sensing of smoke, land, and clouds from the NASA ER-2 during SAFARI 2000, J. Geophys. Res., 108(D13), 8502, doi:10.1029/2002JD003207, 2003.

Klett J. D.: Stable analytical inversion solution for processing lidar returns, Applied Optics, 20, 211–220, 1981.

Li L., Heymsfield, G. M., Racette, P. E., Tian, L., and Zenker, E.: A 94-GHz cloud radar system on a NASA high-altitude ER-2 aircraft, J. Atmos. Oceanic. Technol., 21(9), 1378–1388, 2004.

McFarquhar, G. M. and Heymsfield, A. J.: Microphysical characteristics of three cirrus anvils sampled during the Central Equatorial Pacific Experiment (CEPEX), J. Atmos. Sci, 52, 2401–2423, 1996.

McGill M. J., Hlavka, D. L. , Hart, W. D., Spinhirne, J. D., Scott, V. S. and Schmid, B.: The Cloud Physics Lidar: Instrument description and initial measurement results. Applied Optics, 41, 3725–3734, 2002.

McGill M. J., Hlavka, D.L. , Hart, W. D., Welton, E. J., and Campbell, J. R.: Airborne lidar measurements of aerosol optical properties during SAFARI 2000. J. Geophys. Res., 108, 8493, 2003.

McGill, M. J., Li, L., Hart, W. D., Heymsfield, G. M., Hlavka, D. L., Racette, P. E., Tian, L., Vaughan, M. A., and Winker, D. M.: Combined lidar-radar remote sensing: Initial results from CRYSTAL-FACE, J. Geophys. Res., 109, D07203, 2004.

Noel V. and Chepfer, H.: Study of ice crystal orientation in cirrus clouds based on satellite polarized radiance measurements, J. Atmos. Sci., 61, 2073–2081, 2004.

Noel, V., Winker, D. M., McGill, M., and Lawson, P.: Classification of particle shapes from lidar depolarization ratio in convective ice clouds compared to in situ observations during CRYSTAL-FACE, J. Geophys. Rev., 109, D24213, 2004.

Platt, C. M. R.: Lidar and Radiometric observations of cirrus clouds, J. Atmos. Sci., 30, 1191–1204, 1973.

Platt C. M. R., Scott, J. C. and Dilley, A. C.: Remote sensing of high clouds. Part VI: Optical properties of midlatitude and tropical cirrus, J. Atmos. Sci., 44, 4, 729–747, 1987.

Platt C. M. R., Winker, D. M., Vaughan, M. A., and Miller, S. D.: Backscatter-to-extinction in the Top Layers of Tropical Mesoscale Convective Systems and in Isolated Cirrus from LITE observations. J. Appl. Met., 38, 1330–1345, 1999.

Spinhirne J. D., Reagan, J. A. and Herman, B. M.: Vertical Distribution of Aerosol Extinction Cross-Section and Inference of Aerosol Imaginary Index in the Troposphere by Lidar Technique. J. App. Met., 19, 4, 426–438, 1980.

Stephens, G. L., Tsay, S.-C., Stackhouse, P. W. and Flatau, P. J.: The relevance of the microphysical and radiative properties of cirrus clouds to climate and climate feedback J. Atmos. Sci., 47, 1742–1753, 1990.

Winker, D. M., Pelon, J., and McCormick, M. P.: The CALIPSO mission: Spaceborne lidar for observation of aerosols and clouds, Proc. SPIE, 4893, 1–11, 2003.

Winker D. M.: Accounting for Multiple Scattering in Retrievals from Space Lidar, Proc. SPIE 5059, 128–139, 2003.

Wylie, D. P., Menzel, W. P., Woolf, H. M., and Strabala, K. L.: Four Years of Global Cirrus clouds statistics using HIRS, J. Climate 7, 315–335, 1994.

Zwally, H. J., Schutz, B., Abdalati, W., Abshire, J., Bentley, C., Brenner, A., Bufton, J., Dezio, J., Hancock, D., Harding, D., Herring, T., Minster, B., Quinn, K., Palm, S., Spinhirne, J., and Tomas, R.: ICESat's Laser Measurements of Polar Ice, Atmosphere, Ocean, and Land, J. Geodyn., 34, 405–445, 2002.