Adjustment of wind fields for application in air pollution modeling

Abstract

A technique to construct an accurately specified wind field, which can be used as input to air pollution and meteorological models, is developed based on variational calculus principles, and extends prior studies using this approach. Two-dimensional wind data sets over the region are constructed using a1/ r 2 interpolation procedure. These sets of wind data are subject to two constraints, satisfaction of the continuity equation and observed vorticity, so that the resultant adjusted wind field retains the flow characteristics of the observed data and is mass conservative. The direct-differencing technique is used to compute the vertical wind field from the adjusted horizontal field. Cases of constant and variable atmospheric density are considered. The divergence of the adjusted wind field is found to be considerably reduced, and the vertical component of vorticity of the observed wind field is preserved by the adjusted field. The vertical wind fields obtained are representative of ‘well-behaved’ wind fields with minimal abnormalities in magnitude and distribution.