Development of a Cirrus Parameterization Scheme: Performance Studies in HIRLAM

Danče Zurovac-Jevtić Department of Meteorology, Stockholm University, Stockholm, Sweden

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Abstract

A parameterization scheme for the formation and maintenance of cirrus is presented. The technique combines the description of the microphysical processes specific to ice with the observational experience of cirrus behavior. The scheme is a further development of the cloud parameterization approach presented in The performance of this cirrus scheme is tested with the High-Resolution Limited Area Model (HIRLAM).

Ice crystals are assumed to form through homogeneous freezing of solution droplets, at temperatures below −38°C, provided that the relative humidity exceeds a temperature-dependent threshold for the relative humidity with respect to ice. The onset of ice crystal nucleation is followed by the relaxation of the cloud water and relative humidity toward the quasi-steady state, forced by the large-scale convergence of water vapor. Ice crystals, horizontally advected from the neighboring grid boxes, enable spreading of cirrus whenever the relative humidity exceeds saturation.

Performance studies with HIRLAM show that there is a large structural agreement between the satellite images and the forecasted cirrus in the extent and the pattern of the cover. The predicted mean ice water content decreases with the decreasing temperature, reflecting the temperature-dependent behavior of the measured data. In a series of sensitivity tests the most sensitive scheme parameters are revealed and analyzed.

Corresponding author address: Dr. Dance Zurovac-Jevtic, Department of Meteorology, Stockholm University, S-106 91 Stockholm, Sweden.

Abstract

A parameterization scheme for the formation and maintenance of cirrus is presented. The technique combines the description of the microphysical processes specific to ice with the observational experience of cirrus behavior. The scheme is a further development of the cloud parameterization approach presented in The performance of this cirrus scheme is tested with the High-Resolution Limited Area Model (HIRLAM).

Ice crystals are assumed to form through homogeneous freezing of solution droplets, at temperatures below −38°C, provided that the relative humidity exceeds a temperature-dependent threshold for the relative humidity with respect to ice. The onset of ice crystal nucleation is followed by the relaxation of the cloud water and relative humidity toward the quasi-steady state, forced by the large-scale convergence of water vapor. Ice crystals, horizontally advected from the neighboring grid boxes, enable spreading of cirrus whenever the relative humidity exceeds saturation.

Performance studies with HIRLAM show that there is a large structural agreement between the satellite images and the forecasted cirrus in the extent and the pattern of the cover. The predicted mean ice water content decreases with the decreasing temperature, reflecting the temperature-dependent behavior of the measured data. In a series of sensitivity tests the most sensitive scheme parameters are revealed and analyzed.

Corresponding author address: Dr. Dance Zurovac-Jevtic, Department of Meteorology, Stockholm University, S-106 91 Stockholm, Sweden.

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  • Hansen Sass, B., L. Rontu, and P. Räisänen, 1994: HIRLAM-2 radiation scheme: Documentation and tests. Tech. Rep. 16, 42 pp. [Available from SMHI, S-601 76 Norrköping, Sweden.].

  • Harris, J. E., 1997: Atmospheric radiation and atmospheric humidity. Quart. J. Roy. Meteor. Soc.,123, 2173–2187.

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

  • Heymsfield, A. J., and C. M. R. Platt, 1984: 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, 846–855.

  • ——, and R. M. Sabin, 1989: Cirrus crystal nucleation by homogeneous freezing of solution droplets. J. Atmos. Sci.,46, 2252–2264.

  • ——, and L. M. Miloshevich, 1995: Relative humidity and temperature influence on cirrus formation and evolution: Observations from wave clouds in FIRE II. J. Atmos. Sci.,52, 4302–4326.

  • Huang, X. Y., A. Cederskov, and E. Källen, 1994: A comparison between digital filtering initialization and nonlinear normal-mode initialization in a data assimilation system. Mon. Wea. Rev.,122, 1001–1015.

  • Jensen, J. E., and O. B. Toon, 1994: Ice nucleation in the upper troposphere: Sensitivity to aerosol number density, temperature, and cooling rate. Geophys. Res. Lett.,21, 2019–2022.

  • Källen, E., Ed., 1996: HIRLAM documentation manual, Level 2–5, 215 pp. [Available from SMHI, S-601 76 Norrköping, Sweden.].

  • Mitchell, D. L., 1991: Evolution of snow size spectra in cyclonic storms. Part II: Deviation from the exponential form. J. Atmos. Sci.48, 1885–1899.

  • ——, S. Chai, Y. Liu, A. J. Heymsfield, and D. Yayi, 1996: Modeling cirrus clouds. Part I: Treatment of bimodal size spectra and case study analysis. J. Atmos. Sci.,53, 2952–2966.

  • Pruppacher, H. R., and J. D. Klett, 1978: Microphysics of Clouds and Precipitation. D. Reidel, 714 pp.

  • Sassen, K., and G. C. Dodd, 1988: Homogeneous nucleation rate for highly supercooled cirrus cloud droplets. J. Atmos. Sci.,45, 1357–1369.

  • Savijärvi, H., 1990: Fast radiation parameterization schemes for mesoscale and short-range forecast models. J. Appl. Meteor.,29, 437–447.

  • Starr, D. O’C., and S. K. Cox, 1985: Cirrus clouds. Part I: A cirrus cloud model. J. Atmos. Sci.,42, 2663–2681.

  • Sundqvist, H., 1993: Parameterization of clouds in large scale numerical models. Aerosol–Cloud–Climate Interactions. P. V. Hobbs, Ed., Academic Press, 175–203.

  • ——, 1995: An approach to treatment of mixed phase hydrometeors in GCMs. Workshop on cloud microphysics parameterizations in global atmospheric circulation models. WMO Tech. Document WMO-TD 713, World Climate Research Programme of ICSU-IOC-WMO, Geneva, Switzerland, 155–166.

  • ——, E. Berge, and J. E. Kristjansson, 1989: Condensation and cloud parameterization studies with a mesoscale numerical weather prediction model. Mon. Wea. Rev.,117, 1641–1657.

  • Wylie, D. P., W. P. Menzel, H. M. Woolf, and K. I. Strabala, 1994: Four years of global cirrus cloud statistics using HIRS. J. Climate,7, 1972–1986.

  • Wyser, K., 1997: The effective radius in ice clouds. Rep. DM-78, Department of Meteorology, Stockholm University, Stockholm, Sweden, 35 pp. [Available from Department of Meteorology, Stockholm University, S-10691 Stockholm, Sweden.].

  • Zurovac-Jevtic, D., 1996: Experiments with a cirrus parameterization scheme in HIRLAM. Rep. DM-73, Department of Meteorology, Stockholm University, Stockholm, Sweden, 35 pp. [Available from Department of Meteorology, Stockholm University, S-10691 Stockholm, Sweden.].

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