Numerical studies on a global barotropic vorticity equation model of the atmosphere /
Samuel Y.K. Yee, Ralph Shapiro.

Description

Main Author

Yee, Samuel Y. K.

Related Names

Shapiro, Ralph, author.
U.S. Air Force Geophysics Laboratory.

Language(s)

English

Published

Hanscom AFB, Massachusetts : Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, 1979.

Subjects

Vortex-motion.
Numerical weather forecasting.
Numerical integration.
Atmospheric models.
Atmospheric circulation.
Atmosphere > Atmosphere / Mathematical models.
Numerical integration.
Numerical weather forecasting.
Vortex-motion.
Atmospheric circulation.
Atmospheric models.
Atmosphere > Atmosphere / Mathematical models.

Summary

Numerical experiments have been designed to study the suitability of certain numerical methods commonly used in the numerical modeling of the atmosphere. Specifically, we conducted experiments to address the following: (1) What effect does a Shapiro-type filter have on the results of a numerical time-integration? (2) What are the capabilities and limitations of numerical approximations such as second-order finite-difference approximations in numerical time-integrations? The Shapiro filter is found to be very effective in the removal of computation noise and is therefore useful for insuring computational stability in a long-term time-integration. For dynamically stable flows, numerical errors due to truncation and round-off are amplified by the dynamics of the stable system. Numerical methods such as second order finite-difference approximations, together with a Shapiro-type filter, are adequate in yielding approximate solutions to the modeling differential equations. For dynamically unstable flows, numerical errors are amplified as part of the dynamics of the unstable system. The use of finite-difference approximations may yield solutions which bear no resemblance whatsoever to the true solution of the differential equations. It is postulated that interactions among long wave computational modes and physical modes in a numerical model may prove to be another major obstacle in the numerical prediction of an unstable flow. (Author).

Note

Research supported by the Air Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, Hanscom AFB, Massachusetts.
Meteorology Division Project 2310.
ADA084487 (from http://www.dtic.mil).
"12 December 1979."

Physical Description

32 pages : illustrations ; 28 cm.

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