High-Order, High-Pass Implicit Filters for Evaluating Information within Finite Areas

In this study high-order, high-pass implicit filters are introduced. They represent symmetric filters in an implicit formulation. In this investigation their use within a finite region is examined. The effects of the boundary are investigated and comparisons with spectral methods are made to evaluate the response of the high-pass filter and to test the desirability of Neumann and reflective boundary conditions. These high-order, high-pass implicit filters are shown to be a useful tool to help evaluate and interpret meteorological fields.