The aliased and the de-aliased spectral models of the shallow water equations

• Other Authors: Chen, Xiong-shan, 1933- (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Numerical weather forecasting; Weather forecasting > Mathematical models
• Online Access: http://purl.flvc.org/fsu/fd/FSU_agg9483

"The most widely used spectral models with the transform method are the de-aliased spectral model in which the de-aliased technique is used in the discrete Fourier transform according to the 3/2-rule. From the viewpoint of the Walsh-Hadamard transform, the multiplications of the values of the variables on the gridpoints do not yield the aliasing terms. In the shallow water equations, we compare the aliased spectral model with the de-aliased spectral model using the initial conditions of the Rossby-Haurwitz wave and the FGGE data. The aliased spectral models are more accurate and more efficient than the de-aliased spectral models. For the same wavenumber truncation, the computational amount of the aliased spectral model is only 60 percent of the de-aliased spectral model. We have not yet discovered the phenomenon of the nonlinear computational instability induced by the aliasing terms in the long time integration of the aliased spectral models. Thus, in the spectral models with the transform method the necessity of using the 3/2-rule in the discrete Fourier transform may be viewed with suspicion"--Abstract. === Typescript. === "Spring Semester, 1991." === "Submitted to the Department of Meteorology in partial fulfillment of the requirements for the degree of Master of Science." === Advisor: Richard L. Pfeffer, Professor Directing Thesis. === Includes bibliographical references (leaves 92-95).