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Original Research Papers

Numerical studies of frontal motion in the atmosphere-I

Authors:

A. Kasahara ,

Courant Institute of Mathematical Sciences, New York University, US
About A.

Preaent affiliation: National Center for Atmospheric Research, Boulder, Colorado

The research reported in this paper was performed under Contract Nonr-286(66) with the Office of Naval Research, U.S. Navy and under Contract AT(30-1)-1480 with the U.S. Atomic Energy Commission. Reproduction in whole or in part is permitted for any purpose of the United States Government.

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E. Isaacson,

Courant Institute of Mathematical Sciences, New York University, US
About E.
The research reported in this paper was performed under Contract Nonr-286(66) with the Office of Naval Research, U.S. Navy and under Contract AT(30-1)-1480 with the U.S. Atomic Energy Commission. Reproduction in whole or in part is permitted for any purpose of the United States Government.
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J. J. Stoker

Courant Institute of Mathematical Sciences, New York University, US
About J. J.
The research reported in this paper was performed under Contract Nonr-286(66) with the Office of Naval Research, U.S. Navy and under Contract AT(30-1)-1480 with the U.S. Atomic Energy Commission. Reproduction in whole or in part is permitted for any purpose of the United States Government.
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Abstract

The motion of frontal disturbances in the atmosphere is studied by the numerical solution of differential equations based upon a two-layer model of an incompressible fluid on a rotating earth. The density of each layer is assumed to be constant. The upper and lower fluids correspond respectively to warm and cold air. In this first attempt, only the motion of the lower cold air layer is studied by assuming, in effect, that the dynamics of the perturbations in the upper warm air layer can be neglected.

The numerical study of this simple mechanical model shows that even though thermodynamic processes have been ignored, the occlusion process, characteristic for warm and cold fronts, develops from an initially sinusoidal frontal pattern. Two cases of different initial conditions are examined. Case A: Only the east-west component of wind velocity is initially geostrophic. Case B: Both east-west and north-south components are initially geostrophic. In both cases, computations indicate that the cold front propagates faster than the warm front and that a relatively strong mass convergence zone appears behind the cold front only. This fact suggests the occurrence of severe storms associated with cold fronts, but not with warm fronts in the atmosphere. The numerical method developed here to calculate the movement of the front is based on following the motion of the material “particles” at the front. This method has applications to the numerical solution of a certain class of hydrodynamic flow problems in which the entire boundary of the domain of integration is not given a priori, but must be determined (so-called free-boundary problems).

How to Cite: Kasahara, A., Isaacson, E. and Stoker, J.J., 2012. Numerical studies of frontal motion in the atmosphere-I. Tellus A: Dynamic Meteorology and Oceanography, 17(3), pp.261–276. DOI: http://doi.org/10.3402/tellusa.v17i3.9152
Published on 01 Jan 2012.
Peer Reviewed

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