A Model of the Effect of Aerosols on Urban Climates with Particular Applications to the Los Angeles Basin

Abstract

A one-dimensional, time-dependent model of the boundary layer has been developed to study the effects of pollutants an local meteorological variables. Radiative terms in the model are computed using a fourstream discrete-ordinate method, convective terms are parameterized at the surface using transfer coefficients, and dynamical terms are evaluated from available data. The model is compared initially to the Great Plains data with good results. The results of several model runs with varying types of pollutant concentrations are then discussed. The dominant conclusion that can be drawn from these results is that strong compensation between radiative and convective effects and between low-level heating and inversion rise act to minimize the effect of urban pollutants on surface and atmospheric temperatures. The model results also show that urban pollutants tend to warm the surface slightly and, possibly, to suppress the rate of inversion rise.