On the impact of vertical resolution in the numerical forecasting of fog

In the NWP literature, numerous studies aimed to determine the influence of horizontal resolution on the representation of various mesoscale weather phenomena and the overall accuracy of numerical weather forecasts. Some weather phenomena have limited vertical extension while still exhibiting distinct features in their vertical structure, such as fog and other boundary layer clouds. This suggests a potential sensitivity to the vertical resolution used to generate numerical forecasts of sensitive ceiling and visibility parameters.

Here, the COBEL one-dimensional fog model is used to perform sensitivity numerical experiments of radiation fog formation and evolution. Results show that the overall evolution of a fog layer is indeed dependent on the vertical resolution used in the simulations. The influence of vertical resolution on computed radiative cooling rates and turbulent fluxes and their impact on the vertical growth of the fog layer and the evolution of the fog water content profile are examined.