Hail Growth by Stochastic Collection in a Cumulus ModelSource: Journal of the Atmospheric Sciences:;1972:;Volume( 029 ):;issue: 001::page 135DOI: 10.1175/1520-0469(1972)029<0135:HGBSCI>2.0.CO;2Publisher: American Meteorological Society
Abstract: A one-dimensional, time-dependent numerical model of a cumulus cloud is presented that generates hail and radar reflectivities at realistic rates. The distribution of hydrometeors evolves with time as a result of condensation, sublimation, stochastic collection through collision and coalescence, sedimentation, drop freezing, and drop breakup. A total of 40 mass categories, each twice the mass of the former, corresponding to radii from 2.5 ?m to 2 cm, are used to determine the ice and hail distribution. The first 31 categories up to a radius of 2.5 mm are used for the water drop distribution. Radar reflectivities are computed from Mie scattering theory for water and ice spheres in each category, then summed to give the reflectivities that can be compared to those observed by radar. Only the updraft radius at the earth's surface, the mixing coefficients, and the initial droplet distribution at cloud base are arbitrarily specified. Four initial droplet distributions are studied separately to determine their effect on hail growth rates and the water drop and hail distributions.
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contributor author | Danielsen, E. F. | |
contributor author | Bleck, R. | |
contributor author | Morris, D. A. | |
date accessioned | 2017-06-09T14:16:13Z | |
date available | 2017-06-09T14:16:13Z | |
date copyright | 1972/01/01 | |
date issued | 1972 | |
identifier issn | 0022-4928 | |
identifier other | ams-16098.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4151843 | |
description abstract | A one-dimensional, time-dependent numerical model of a cumulus cloud is presented that generates hail and radar reflectivities at realistic rates. The distribution of hydrometeors evolves with time as a result of condensation, sublimation, stochastic collection through collision and coalescence, sedimentation, drop freezing, and drop breakup. A total of 40 mass categories, each twice the mass of the former, corresponding to radii from 2.5 ?m to 2 cm, are used to determine the ice and hail distribution. The first 31 categories up to a radius of 2.5 mm are used for the water drop distribution. Radar reflectivities are computed from Mie scattering theory for water and ice spheres in each category, then summed to give the reflectivities that can be compared to those observed by radar. Only the updraft radius at the earth's surface, the mixing coefficients, and the initial droplet distribution at cloud base are arbitrarily specified. Four initial droplet distributions are studied separately to determine their effect on hail growth rates and the water drop and hail distributions. | |
publisher | American Meteorological Society | |
title | Hail Growth by Stochastic Collection in a Cumulus Model | |
type | Journal Paper | |
journal volume | 29 | |
journal issue | 1 | |
journal title | Journal of the Atmospheric Sciences | |
identifier doi | 10.1175/1520-0469(1972)029<0135:HGBSCI>2.0.CO;2 | |
journal fristpage | 135 | |
journal lastpage | 155 | |
tree | Journal of the Atmospheric Sciences:;1972:;Volume( 029 ):;issue: 001 | |
contenttype | Fulltext |