Development and Evaluation of a New Algorithm for Estimating TIBL Height

A meteorological condition that can produce high concentrations in coastal environments is referred to as shoreline fumigation. Past studies have shown that an important parameter for predicting accurate concentrations under this conditions is the height of the thermal internal boundary layer (TIBL) versus inland distance. While several analytical methods have been developed for estimating TIBL height, one method, referred to as the Weisman equation, has been shown to provide better estimates than several other methods when compared against field observations. The Weisman equation was developed based on the assumption of constant overwater temperature lapse rate, uniform overland wind profile, constant surface heat flux, and zero heat flux at the top of the TIBL. This paper presents a new equation for predicting the TIBL height which does not include these assumptions and which is based on sound scientific principles. The new equation was tested against a wind tunnel and field database of TIBL heights and the new equation agreed significantly better with observations (at the 95% confidence level) than the existing Weisman equation. Based on this study, the new TIBL algorithm should be inserted into an appropriate shoreline dispersion model so that the overall performance of model with this algorithm can be evaluated against field and wind tunnel databases.