Why does fog deepen?: An analytical perspective

Izett, J.G.; van de Wiel, B.J.H.

doi:10.3390/ATMOS11080865

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 model
Boundary-layer
Fog
Fog dynamics
Large-eddy simulation
Observations

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