Digital filters, originally developed in the context of Discrete-time Signal Processing (DSP), have recently been used for the analysis and solution of problems in geophysics. In the field of numerical weather prediction these filters have been applied to the problems of initialization and objective analysis, and they have considerable potential for other applications in NWP.
The theory of digital filters is presented in this report, with the interests of atmospheric modellers in mind. Both non-recursive and recursive filters are discussed, and applications of both of these to initialization are described. The purpose of the report is to provide a gentle introduction to digital filtering, with emphasis on the aspects thought to be most important for NWP applications. The report should give the reader easier access to the more recondite treatments of filtering available in the DSP literature.
Note: Figures not included. Please contact author (Peter.Lynch@met.ie ) for a complete paper copy of this report.