A Fast Numerical Method for Explicit Integration of Primitive Equations Near the Poles,
Abstract
In this paper the three-point method is analyzed and compared to the Fourier method for the numerical solution of the primitive equations in the polar regions. It is shown that the original definition of the latitudinally-dependent parameters of the three-point method results in insufficient frequency reduction compared to the Fourier method. A suitable redefinition of these parameters gives a three-point method that is stable with the time step of the Fourier method, although to prevent the modified frequency from becoming zero in high latitudes requires excessive computation. Consequently the three-point and Fourier methods are combined to form a hybrid method, which is twice as fast as the original Fourier method. An additional doubling of the speed of the hybrid method is achieved by a simple improvement of the Fourier Transform used in the Fourier method. The hybrid method has allowed the time step of the Rand atmospheric GCM to be increased from six to ten minutes with a resultant decrease in time requirement of 37%.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1976
- Accession Number
- ADA037908
Entities
People
- Michael E. Schlesinger
Organizations
- RAND Corporation