In most U.S. Army atmospheric dispersion models, the pasquill methodology is used to estimate stability in the boundary layer. As a result, there are discontinuities in calculated dispersion among the six stability classes. Furthermore, corrections for surface conditions (i.e., fields, urban areas, or forests) are also discrete functions. Recent theoretical developments provide the basis for revising this methodology using principles of monin-obukhov and convective similarity theory. An algorithm for determining stability as a continuous function is developed for use on a personal computer. This algorithm requires input of basic observations such as wind speed, cloudiness, surface roughness and albedo, and moisture content of the ground. The methodology is sufficiently general that it is valid for all types of underlying surfaces and produces an estimate of stability that is continuous in time and space. Profiles of wind, temperature, and turbulence can also be readily calculated by this algorithm, for direct use in dispersion models.
