Clouds and Shortwave Fluxes at Nauru. Part I: Retrieved Cloud Properties

Sally A. McFarlane Program in Atmospheric and Oceanic Sciences, University of Colorado, Boulder, Colorado

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K. Franklin Evans Program in Atmospheric and Oceanic Sciences, University of Colorado, Boulder, Colorado

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Abstract

The datasets currently being collected at the Atmospheric Radiation Measurement (ARM) program's sites on the islands of Nauru and Manus represent the longest time series of ground-based cloud measurements available in the tropical western Pacific region. In this and a companion paper, a shortwave flux closure study is presented using observations collected at the Nauru site between June 1999 and May 2000. This paper presents frequency of occurrence of nonprecipitating liquid and ice clouds detected by the millimeter wavelength cloud radar (MMCR) and statistics of retrieved microphysical properties. The companion paper presents results from a closure study in which the retrieved cloud properties are input to a radiative transfer model, and the modeled surface fluxes are compared to observations. The liquid cloud properties are retrieved from MMCR and microwave radiometer (MWR) measurements using a Bayesian retrieval technique. Properties of ice phase clouds are retrieved from MMCR measurements using regression equations based on in situ observations taken during the Central Equatorial Pacific Experiment (CEPEX). Nonprecipitating liquid clouds were observed at Nauru in 35% of the radar observations. These clouds were primarily shallow cumulus with bases less than 1 km. Of the retrieved liquid clouds, 90% had liquid water path less than 100 g m−2. The average retrieved effective radius was 7.5 μm. The frequency of liquid cloud detection and height of the liquid cloud base showed a clear diurnal cycle, which is most likely related to the island effect and the existence of the Nauru cloud plume. Ice clouds with no underlying liquid clouds were detected in 16.5% of the radar observations and ice clouds above liquid clouds in 7.7% of the observations. The mean retrieved IWP of the radar-detected ice clouds was 22.1 g m−2, and the mean effective diameter retrieved was 72 μm. Large monthly variability was seen in both the amount of cirrus detected and the retrieved ice water path. Ice clouds were observed by the radar more frequently at night than during the day at Nauru, but there was no clear diurnal trend in the retrieved microphysical properties.

Corresponding author address: Dr. Sally A. McFarlane, Pacific Northwest National Laboratory, P.O. Box 999/MS K9-24, Richland, WA 99352. Email: Sally.McFarlane@pnl.gov

Abstract

The datasets currently being collected at the Atmospheric Radiation Measurement (ARM) program's sites on the islands of Nauru and Manus represent the longest time series of ground-based cloud measurements available in the tropical western Pacific region. In this and a companion paper, a shortwave flux closure study is presented using observations collected at the Nauru site between June 1999 and May 2000. This paper presents frequency of occurrence of nonprecipitating liquid and ice clouds detected by the millimeter wavelength cloud radar (MMCR) and statistics of retrieved microphysical properties. The companion paper presents results from a closure study in which the retrieved cloud properties are input to a radiative transfer model, and the modeled surface fluxes are compared to observations. The liquid cloud properties are retrieved from MMCR and microwave radiometer (MWR) measurements using a Bayesian retrieval technique. Properties of ice phase clouds are retrieved from MMCR measurements using regression equations based on in situ observations taken during the Central Equatorial Pacific Experiment (CEPEX). Nonprecipitating liquid clouds were observed at Nauru in 35% of the radar observations. These clouds were primarily shallow cumulus with bases less than 1 km. Of the retrieved liquid clouds, 90% had liquid water path less than 100 g m−2. The average retrieved effective radius was 7.5 μm. The frequency of liquid cloud detection and height of the liquid cloud base showed a clear diurnal cycle, which is most likely related to the island effect and the existence of the Nauru cloud plume. Ice clouds with no underlying liquid clouds were detected in 16.5% of the radar observations and ice clouds above liquid clouds in 7.7% of the observations. The mean retrieved IWP of the radar-detected ice clouds was 22.1 g m−2, and the mean effective diameter retrieved was 72 μm. Large monthly variability was seen in both the amount of cirrus detected and the retrieved ice water path. Ice clouds were observed by the radar more frequently at night than during the day at Nauru, but there was no clear diurnal trend in the retrieved microphysical properties.

Corresponding author address: Dr. Sally A. McFarlane, Pacific Northwest National Laboratory, P.O. Box 999/MS K9-24, Richland, WA 99352. Email: Sally.McFarlane@pnl.gov

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  • Albrecht, B. A., 1981: Parameterization of trade-cumulus cloud amounts. J. Atmos. Sci., 38 , 97105.

  • Atlas, D., S. Y. Matrosov, A. J. Heymsfield, M-D. Chouh, and D. B. Wolff, 1995: Radar and radiation properties of ice clouds. J. Appl. Meteor., 34 , 23292345.

    • Search Google Scholar
    • Export Citation
  • Brown, P. R., A. J. Illingworth, A. J. Heymsfield, G. M. McFarquhar, K. A. Browning, and M. Gosset, 1995: The role of spaceborne millimeter-wave radar in the global monitoring of ice cloud. J. Appl. Meteor., 34 , 23462366.

    • Search Google Scholar
    • Export Citation
  • Chen, S. S., and R. A. Houze, 1997: Diurnal variation and life-cycle of deep convective systems over the tropical Pacific warm pool. Quart. J. Roy. Meteor. Soc., 123 , 357388.

    • Search Google Scholar
    • Export Citation
  • Clothiaux, E. E., G. G. Mace, T. P. Ackerman, T. J. Kane, J. D. Spinhirne, and V. S. Scott, 1998: An automated algorithm for detection of hydrometeor returns in micropulse lidar data. J. Atmos. Oceanic Technol., 15 , 10351042.

    • Search Google Scholar
    • Export Citation
  • Clothiaux, E. E., and Coauthors, 1999: The Atmospheric Radiation Measurement program cloud radars: Operational modes. J. Atmos. Oceanic Technol., 16 , 819827.

    • Search Google Scholar
    • Export Citation
  • Clothiaux, E. E., T. P. Ackerman, G. G. Mace, K. P. Moran, R. T. Marchand, M. A. Miller, and B. E. Martner, 2000: Objective determination of cloud heights and radar reflectivities using a combination of active remote sensors at the Atmospheric Measurement Program Cloud and Radiation Test Bed (ARM CART) sites. J. Appl. Meteor., 39 , 645665.

    • Search Google Scholar
    • Export Citation
  • Comstock, J. M., and K. Sassen, 2001: Retrieval of cirrus cloud radiative and backscattering properties using combined lidar and infrared radiometer (LIRAD) measurements. J. Atmos. Oceanic Technol., 18 , 16581673.

    • Search Google Scholar
    • Export Citation
  • Dong, X., T. P. Ackerman, E. E. Clothiaux, P. Pilewskie, and Y. Han, 1997: Microphysical and radiative properties of boundary layer stratiform clouds deduced from ground-based measurements. J. Geophys. Res., 102 , 2382923843.

    • Search Google Scholar
    • Export Citation
  • Duynkerke, P. G., 1998: Dynamics of cloudy boundary layers. Clear and Cloudy Boundary Layers, A. A. M. Holtslag and P. G. Duynkerke, Eds., Royal Netherlands Academy of Arts and Sciences, 199–218.

    • Search Google Scholar
    • Export Citation
  • French, J. R., G. Vali, and R. D. Kelly, 2000: Observations of microphysics pertaining to the development of drizzle in warm, shallow cumulus clouds. Quart. J. Roy. Meteor. Soc., 126 , 415443.

    • Search Google Scholar
    • Export Citation
  • Frisch, A. S., C. W. Fairall, and J. B. Snider, 1995: Measurement of stratus cloud and drizzle parameters in ASTEX with a Ka-band Doppler radar and a microwave radiometer. J. Atmos. Sci., 52 , 27882799.

    • Search Google Scholar
    • Export Citation
  • Frisch, A. S., G. Feingold, C. W. Fairall, T. Uttal, and J. B. Snider, 1998: On cloud radar and microwave radiometer measurements of stratus cloud liquid water profiles. J. Geophys. Res., 103 , 2319523197.

    • Search Google Scholar
    • Export Citation
  • Fu, R., A. D. Del Genio, and W. B. Rossow, 1990: Behavior of deep convective clouds in the tropical Pacific deduced from ISCCP radiances. J. Climate, 3 , 11291152.

    • Search Google Scholar
    • Export Citation
  • Han, Y., and E. R. Westwater, 2000: Analysis and improvement of tipping calibration for ground-based microwave radiometers. IEEE Trans. Geosci. Remote Sens., 38 , 118.

    • Search Google Scholar
    • Export Citation
  • Heymsfield, A. J., and G. M. McFarquhar, 1996: High albedos of cirrus in the tropical Pacific warm pool: Microphysical interpretations from CEPEX and from Kwajalein, Marshall Islands. J. Atmos. Sci., 53 , 24242450.

    • Search Google Scholar
    • Export Citation
  • Heymsfield, A. J., K. M. Miller, and J. D. Spinhirne, 1990: The 27–28 October 1986 FIRE IFO cirrus case study: Cloud microstructure. Mon. Wea. Rev., 118 , 23132328.

    • Search Google Scholar
    • Export Citation
  • Intrieri, J. M., G. L. Stephens, W. L. Eberhard, and T. Uttal, 1993: A method for determining cirrus cloud particle sizes using lidar and radar backscatter technique. J. Appl. Meteor., 32 , 10741082.

    • Search Google Scholar
    • Export Citation
  • Janowiak, J. E., P. A. Arkin, and M. Morrissey, 1994: An examination of the diurnal cycle in oceanic tropical rainfall using satellite and in situ data. Mon. Wea. Rev., 122 , 22962311.

    • Search Google Scholar
    • Export Citation
  • Liao, L., and K. Sassen, 1994: Investigation of relationships between Ka-band radar reflectivity and ice and liquid water contents. Atmos. Res., 34 , 231248.

    • Search Google Scholar
    • Export Citation
  • Liu, C-L., and A. J. Illingworth, 2000: Toward more accurate retrievals of ice water content from radar measurements of clouds. J. Appl. Meteor., 39 , 11301146.

    • Search Google Scholar
    • Export Citation
  • Mace, G. G., and K. Sassen, 2000: A constrained algorithm for retrieval of stratocumulus cloud properties using solar radiation, microwave radiometer, and millimeter cloud radar data. J. Geophys. Res., 105 , 2909929108.

    • Search Google Scholar
    • Export Citation
  • Mace, G. G., T. Ackerman, P. Minnis, and D. Young, 1998: Cirrus layer microphysical properties derived from surface-based millimeter radar and infrared interferometer data. J. Geophys. Res., 103 , 2320723216.

    • Search Google Scholar
    • Export Citation
  • Mace, G. G., A. J. Heymsfield, and M. R. Poellot, 2002: On retrieving the microphysical properties of cirrus clouds using the moments of the millimeter-wavelength Doppler spectrum. J. Geophys. Res.,107, 4815, doi:10.1029/2001JD001308.

    • Search Google Scholar
    • Export Citation
  • Madden, R., and P. Julian, 1994: Observations of the 40–50-day tropical oscillation—A review. Mon. Wea. Rev., 122 , 814837.

  • Mather, J., T. Ackerman, W. Clements, F. Barnes, M. Ivey, L. Hatfield, and R. Reynolds, 1998: An atmospheric radiation and cloud station in the tropical western Pacific. Bull. Amer. Meteor. Soc., 79 , 627642.

    • Search Google Scholar
    • Export Citation
  • Matrosov, S. Y., B. W. Orr, R. A. Kropfli, and J. B. Snider, 1994: Retrieval of vertical profiles of cirrus cloud microphysical parameters from Doppler radar and infrared radiometer measurements. J. Appl. Meteor., 33 , 617626.

    • Search Google Scholar
    • Export Citation
  • Matrosov, S. Y., A. J. Heymsfield, R. A. Kropfli, B. E. Martner, R. F. Reinking, J. B. Snider, P. Piironen, and E. W. Eloranta, 1998: Comparisons of ice cloud parameters obtained by combined remote sensor retrievals and direct methods. J. Atmos. Oceanic Technol., 15 , 184196.

    • Search Google Scholar
    • Export Citation
  • Matrosov, S. Y., A. Korolev, and A. J. Heymsfield, 2002: Profiling ice mass and characteristic particle size from Doppler radar measurements. J. Atmos. Oceanic Technol., 19 , 10031018.

    • Search Google Scholar
    • Export Citation
  • McFarlane, S. A., K. F. Evans, and A. S. Ackerman, 2002: A Bayesian algorithm for the retrieval of liquid water cloud properties from microwave radiometer and millimeter radar data. J. Geophys. Res.,107, 4317, doi:10.1029/2001JD001011.

    • Search Google Scholar
    • Export Citation
  • McFarquhar, G. M., and A. J. Heymsfield, 1996: Microphysical characteristics of three anvils sampled during the Central Equatorial Pacific Experiment. J. Atmos. Sci., 53 , 24012423.

    • Search Google Scholar
    • Export Citation
  • McFarquhar, G. M., and A. J. Heymsfield, 1997: Parameterization of tropical cirrus ice crystal size distributions and implications for radiative transfer: Results from CEPEX. J. Atmos. Sci., 54 , 21872200.

    • Search Google Scholar
    • Export Citation
  • McFarquhar, G. M., A. J. Heymsfield, J. Spinhirne, and B. Hart, 2000: Thin and subvisual tropopause tropical cirrus: Observations and radiative impacts. J. Atmos. Sci., 57 , 18411853.

    • Search Google Scholar
    • Export Citation
  • Moran, K. P., B. E. Martner, D. Welsh, D. Merritt, M. Post, and T. Uttal, 1997: ARM's cloud profiling radar. Preprints, 28th Int. Conf. on Radar Meteorology, Austin, TX, Amer. Meteor. Soc., 296–297.

    • Search Google Scholar
    • Export Citation
  • Nordeen, M. L., P. Minnis, D. R. Doelling, D. Pethick, and L. Nguyen, 2001: Satellite observations of cloud plumes generated by Nauru. Geophys. Res. Lett., 28 , 631634.

    • Search Google Scholar
    • Export Citation
  • Raga, G. B., J. B. Jensen, and M. B. Baker, 1990: Characteristics of cumulus band clouds off the coast of Hawaii. J. Atmos. Sci., 47 , 338355.

    • Search Google Scholar
    • Export Citation
  • Ramanathan, V., and W. Collins, 1991: Thermodynamic regulation of ocean warming by cirrus clouds deduced from observations of the 1987 El Niño. Nature, 351 , 2732.

    • Search Google Scholar
    • Export Citation
  • Randall, D. A., Q. Shao, and M. Branson, 1998: Representation of cloudy boundary layers in climate models. Clear and Cloudy Boundary Layers, A. A. M. Holtslag and P. G. Duynkerke, Eds., Royal Netherlands Academy of Arts and Sciences, 305–322.

    • Search Google Scholar
    • Export Citation
  • Sassen, K., G. G. Mace, Z. Wang, M. R. Poellot, S. M. Sekelsky, and R. E. McIntosh, 1999: Continental stratus clouds: A case study using coordinated remote sensing and aircraft measurements. J. Atmos. Sci., 56 , 23452358.

    • Search Google Scholar
    • Export Citation
  • Sassen, K., R. P. Benson, and J. D. Spinhirne, 2000: Tropical cirrus cloud properties derived from TOGA/COARE airborne polarization lidar. Geophys. Res. Lett., 27 , 673676.

    • Search Google Scholar
    • Export Citation
  • Schneider, T. L., and G. Stephens, 1995: Theoretical aspects of modeling backscattering by cirrus ice particles at millimeter wavelengths. J. Atmos. Sci., 52 , 43674385.

    • Search Google Scholar
    • Export Citation
  • Squires, P., 1956: The micro-structure of cumuli in maritime and continental air. Tellus, 8 , 443444.

  • Squires, P., and J. Warner, 1957: Some measurements in the orographic cloud of the island of Hawaii and in trade wind cumuli. Tellus, 9 , 475494.

    • Search Google Scholar
    • Export Citation
  • Stephens, G. L., and C. M. R. Platt, 1987: Aircraft observations of the radiative and microphysical properties of stratocumulus and cumulus cloud fields. J. Climate Appl. Meteor., 26 , 12431269.

    • Search Google Scholar
    • Export Citation
  • Wang, Z., and K. Sassen, 2002: Cirrus cloud microphysical property retrieval using lidar and radar measurements. Part I: Algorithm description and comparison with in situ data. J. Appl. Meteor., 41 , 218229.

    • Search Google Scholar
    • Export Citation
  • Webster, P. J., and R. Lukas, 1992: The Coupled Ocean–Atmosphere Response Experiment. Bull. Amer. Meteor. Soc., 73 , 13771416.

  • Webster, P. J., C. A. Clayson, and J. A. Curry, 1996: Clouds, radiation, and the diurnal cycle of sea surface temperature in the tropical western Pacific. J. Climate, 9 , 17121730.

    • Search Google Scholar
    • Export Citation
  • Westwater, E. R., and Coauthors, 1999: Ground-based remote sensor observations during PROBE in the tropical western Pacific. Bull. Amer. Meteor. Soc., 80 , 257270.

    • Search Google Scholar
    • Export Citation
  • Westwater, E. R., B. B. Stankov, D. Cimini, Y. Han, J. A. Shaw, B. M. Lesht, and C. N. Long, 2003: Radiosonde humidity soundings and microwave radiometers during Nauru99. J. Atmos. Oceanic Technol., 20 , 953971.

    • Search Google Scholar
    • Export Citation
  • Widener, K. B., and C. N. Long, cited 2002: Nauru Island effect study—Installation and preliminary data. Proc. 12th Atmospheric Radiation Measurement Program Science Team Meeting, St. Petersburg, FL, U.S. Department of Energy. [Available online at http://www.arm.gov/docs/documents/technical/conf_0204/widener(1)-kb.pdf.].

    • Search Google Scholar
    • Export Citation
  • Yang, P., K. N. Liou, K. Wyser, and D. Mitchell, 2000: Parameterization of the scattering and absorption properties of individual ice crystals. J. Geophys. Res., 105 , 46994718.

    • Search Google Scholar
    • Export Citation
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