We are developing a new meteorological data assimilation
model for the Atmospheric Release Advisory Capability (ARAC) project at Lawrence Livermore National
Laboratory, which provides real-time dose assessments of airborne pollutant releases. The model, ADAPT (Atmospheric Data Assimilation and Parametrization Techniques), builds three dimensional meteorological
fields, which can be used to drive dispersion models or to initialize or evaluate mesoscale models. ADAPT incorporates many new features and substantial improvements over the current ARAC operational models
MEDIC/MATHEW (ARAC, 1997), includihg the use of continuous-terrain variable-resolution grids, the ability to treat assorted meteorological data such as temperatures, pressure, and relative humidity, and a new algorithm
to produce mass-consistent wind fields. In this paper, we will describe the main features of the model, current work on a new atmospheric stability pararneterization, and show example results.