Comparison of the Gaussian Plume Diffusion Model with Experimental Data from Tilbury and Northfleet

摘要

The Gaussian Plume Diffusion Model, using Smith's scheme for exp + sub(z) and various models for exp + sub(y), is compared with measured values of the location and strength of maximum ground level concentration taken during the Tilbury and Northfleet experiments. The position of maximum ground level concentration (xsub(m)) is found to be relatively insensitive to exp + sub(y) and Smith's model for exp + sub(z) is found to predict xsub(m) on average to within 50% for plume heights less than 200 - 400m (dependent on atmosphere stability). Several models for exp + sub(y) are examined by comparing predicted and observed values for the normalised maximum ground level concentration (Xsub(m)) and a modified form of Moore's model for exp + sub(y) is found to give the best overall fit, on average to within 30%. Gifford's release duration dependent model for exp + sub(y) is found to consistently underestimate Xsub(m) by 35 - 45%. This comparison is only a partial validation of the models described above and suggestions are made as to where further work is required. (Atomindex citation 11:502258)