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Saint Louis University: "Fog prediction using a simple numerical model"

Final Report

Note: The following is taken from the final report on this project. A version of the report was published in Pure and Applied Geophysics (155, no. 1, 1999) under the title "Radiation Fog Prediction: Using a Simple Numerical Model".


A simple one-dimensional numerical-analytical model is developed to predict the onset of radiation fog by Meyer and Rao (1995). The model is designed for Air Force forecasters who have access to a personal computer, an early evening surface observation of the dry bulb and dewpoint temperatures, wind speed, estimates of the wetness of the ground, and the lapse rate in the upper boundary layer. The model uses these initial data to predict the diurnal variation of the dry bulb and dewpoint temperatures at 10 m above the surface. In accordance with convectional synoptic observing practices, fog is defined as a restriction of the surface visibility to less than 1000 m. Fog is assumed to occur in the model predictions when the dewpoint depression falls to less than 1°C. Observations, from several Air Force bases for selected days when fog was observed to occur, were used to verify the model. The present model with default parameters appears to predict the onset of fog ahead of its occurrence. Better verification results are expected when site-relevant parameters are used in model predictions.