Editorial Type:
Article
Article Type:
Research Article

Variational Optimization Method for Calculation of Cloud Drop Growth in an Eulerian Drop-Size Framework

Qingfu Liu Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, Norman, Oklahoma

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Yefim L. Kogan Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, Norman, Oklahoma

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Douglas K. Lilly Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, Norman, Oklahoma

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Marat P. Khairoutdinov Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, Norman, Oklahoma

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Print Publication:
01 Oct 1997
DOI:
https://doi.org/10.1175/1520-0469(1997)054<2493:VOMFCO>2.0.CO;2
Page(s):
2493–2504
Restricted access

Abstract

A variational optimization (VO) method that requires specification of only one variable in each bin size for condensation and evaporation calculations in an Eulerian drop-size framework is proposed. The method is tested against the exact solution given by the Lagrangian method using more than 15000 spectra selected from experiments with a three-dimensional large eddy simulation model with explicit microphysics. The results show that the VO method not only conserves the integral parameters of the spectrum, such as drop number, mean radius, liquid water content, and the effective radius, but also provides an accurate calculation of the spectrum itself.

Corresponding author address: Qingfu Liu, CIMMS, University of Oklahoma, 100 E. Boyd, Norman, OK 73019.

Abstract

A variational optimization (VO) method that requires specification of only one variable in each bin size for condensation and evaporation calculations in an Eulerian drop-size framework is proposed. The method is tested against the exact solution given by the Lagrangian method using more than 15000 spectra selected from experiments with a three-dimensional large eddy simulation model with explicit microphysics. The results show that the VO method not only conserves the integral parameters of the spectrum, such as drop number, mean radius, liquid water content, and the effective radius, but also provides an accurate calculation of the spectrum itself.

Corresponding author address: Qingfu Liu, CIMMS, University of Oklahoma, 100 E. Boyd, Norman, OK 73019.

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