This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module
Have an account?
Sign In to write a review.
At the end of the module you should be able to do the following things:
With Regard to the Preconditioning Environment:
• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation
With Regard to Initiation and Growth:
• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth
With Regard to Maintenance Phase:
• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer
With Regard to Dissipation Phase:
• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog
With Regard to Forecasting Fog:
• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog
radiation fog, print, summary, preconditions, formation, growth, maintenance, dissipation, moisture, anticyclones, thermal conductivity, supersaturated, condensation, fog droplets, evaporation, droplet settling, temperature inversion, turbulent mixing, convective mixing, GOES, fog product, persistence, climatology, diurnal, relative humidity
