Print Email Facebook Twitter Why does fog deepen? Title Why does fog deepen?: An analytical perspective Author Izett, J.G. (TU Delft Atmospheric Remote Sensing) van de Wiel, B.J.H. (TU Delft Atmospheric Remote Sensing) Date 2020 Abstract The overall depth of a fog layer is one of the important factors in determining the hazard that a fog event presents. With discrete observations and often coarse numerical grids, however, fog depth cannot always be accurately determined. To address this, we derive a simple analytical relation that describes the change in depth of a fog interface with time, which depends on the tendencies and vertical gradients of moisture. We also present a lengthscale estimate for the maximum depth over which mixing can occur in order for the fog layer to be sustained, assuming a uniform mixing of the vertical profiles of temperature and moisture. Even over several hours, and when coarse observational resolution is used, the analytical description is shown to accurately diagnose the depth of a fog layer when compared against observational data and the results of large-eddy simulations. Such an analytical description not only enables the estimation of sub-grid or inter-observation fog depth, but also provides a simple framework for interpreting the evolution of a fog layer in time. Subject Analytical modelBoundary-layerFogFog dynamicsLarge-eddy simulationObservations To reference this document use: http://resolver.tudelft.nl/uuid:f2921726-4767-4630-927a-f41b2068b081 DOI https://doi.org/10.3390/ATMOS11080865 ISSN 2073-4433 Source Atmosphere, 11 (8), 1-24 Part of collection Institutional Repository Document type journal article Rights © 2020 J.G. Izett, B.J.H. van de Wiel Files PDF atmosphere_11_00865_v2.pdf 1.58 MB Close viewer /islandora/object/uuid:f2921726-4767-4630-927a-f41b2068b081/datastream/OBJ/view