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  • Author or Editor: E. L. Magaziner x
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E. L. Magaziner

Abstract

The simulation of crystal growth by diffusion and by accretion of cloud droplets is incorporated into the Lavoie mesoscale numerical model for lake-effect storms. The model also allows simulation of seeding and its effect on changing the precipitation growth mode from riming to diffusion. Precipitation particle trajectories are computed so that the effects of seeding on snowfall distribution can be simulated. The model's predictions agree well with observations of nonseeded cases and, in terms of computer time, the model is sufficiently practical to allow experimentation with various seeding strategies under various meteorological conditions. Numerical seeding experiments with the model indicate that optimum seeding strategies can shift the characteristic localized heavy snowfalls to areas where their effect will be less damaging.

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E. L. Magaziner
and
H. K. Weickmann

Abstract

The mesoscale, individual-hailstreak structure of hailswaths can markedly affect the analysis of hail suppression experiments that are based on protecting a given area from approaching hailswaths. Calculations reveal that such an experiment may (depending on the size of the protected area and on hailstreak length) be counted as a success even when the hail suppressing activity is ineffective. This phenomenon may have contributed to serious errors in the evaluation of the pilot test program in hail suppression conducted in the Soviet Union during 1961–63, on which consequent programs were based.

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Charles F. Chappell
,
E. L. Magaziner
, and
J. Michael Fritsch

Abstract

Non-iterative methods for computing isobaric wet-bulb temperature and the temperature at the lifted sublimation level are presented. These quantities are then computed by these direct techniques and compared to values derived through iterative methods. In the case of the isobaric wet-bulb temperature, differences in the two methods are less than 1C over normal ranges of atmospheric temperature and pressure for dewpoint depressions <30C. Differences in the two methods are less than 0.03C for the temperature at the lifted sublimation level over the same range of dewpoint depression.

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J. M. Fritsch
,
E. L. Magaziner
, and
C. F. Chappell

Abstract

A technique for generating analytical initial conditions for three-dimensional numerical models is presented. The technique combines trigonometric and other mathematical functions with meteorological constraints to construct an idealized atmosphere which exhibits commonly observed “real” atmosphere structural characteristics. For example, pressure and thermal waves which slope with height, tropopause, low-level moist tongue, phase differences in pressure and thermal waves, and a jet maximum at the tropopause level are all generated by the simple system of equations.

Examples of both mesoscale and synoptic-scale initial conditions are given, and results of integrating the mesoscale initial conditions in a three-dimensional model are shown. The initialization procedure is economical and flexible, and potential applications include testing weather modification sensitivity, finite-difference schemes, lateral boundary formulations, and various subgrid-scale parameterizations.

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