FORMULATION OF THE LATERAL BOUNDARY CONDITIONS FOR THE NCAR LIMITED-AREA MODEL.

Abstract

The Limited-Area Model (LAM) developed at the National Center for Atmospheric Research for use in conjunction with the NCAR Global Circulation Model is described including details of the lateral boundary conditions. One set of experiments is described for which a 2 one-half degree global simulation provides the correct or control data against which 2 one-half degree LAM forecasts are compared. Three cases are considered in which the LAM inflow boundary values are provided by the 2 one-half degree global forecast, a 5 degree global forecast, or are held fixed equal to the initial values. Forecasts produced by the LAM with finer grids (up to 5/8 degree ) are also shown. Although based on simulated data, the results indicate that the Limited-Area Model shows good potential for short-range forecasting.