A Horizontal Telescoping Grid Model with a Vertically Nested Layer Using Bi-Cubic Splines

Abstract

A numerical weather forecasting program using bi-cubic spline fits to the data in the horizontal direction and cubic spline fits in the vertical has been tested using real weather data for a 48 h forecast period. The grid used was a telescoping grid with a region of fine resolution over North America. The model had two global layers and a third limited-area layer between the two, over the region of fine resolution. Orographic effects and simple radiation and moisture codes were included. The model was stable and there were no apparent problems in Reynolds stresses due to the limited-area layer.