Efficient dynamical initialization of a limited area model

Arne M. Bratseth

doi:10.3402/tellusa.v41i1.11818

Efficient dynamical initialization of a limited area model

Tellus

Volume 41 (1989): Issue 1

By: Arne M. Bratseth

Open Access

|Jan 1989

Abstract

The dynamical initialization used in the limited area weather prediction routine at the Norwegian Meteorological Institute is presented. 3 iterations, corresponding to 6 model time steps, are shown to produce an almost noise-free integration. This efficient noise reduction is achieved by means of simple filters which cause the damping rate to depend on horizontal and vertical scales as well as frequency. Normal mode arguments are used to adjust parameters so that modes moving faster than about 70 ms^-1 are suppressed, while modes moving slower than about 30 ms^-1 are retained. Explicit knowledge of the normal modes is not required. Implementation of the scheme is very simple, and it is easily adapted to most existing models.

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