Summary of Marine Stratus and Fog

My understanding of the Powerpoint slides presented by Prof. Peter Taylor for the Fog Dew meeting

Lessons Learned

Slide 2

There is a comparison made between marine and land fog:

Land Fog

• On land, it is mostly radiation fog and there is nocturnal cooling of the land surfaces.
• Stable stratification and light winds and may have drainage flow of cold air to lower locations.
• Uphill winds leading to adiabatic cooling.
• Onshore advection of marine fog in coastal areas.

Marine Fog

• Surface radiation effects are small due to the large heat capacity of water and there is low diurnal temperature variations.
• Moderate to strong winds affect fog and stratus lowering may occur.
• Warm, moist air moving to the colder sea surface of the ocean lead to advection fog.
• Tidal mixing of the sea affect fog formation and stability. Eg: Yellow Sea.

Slide 3-5

The setup used:

Above the water surface, there is a steady, well-mixed boundary layer so potential temperature(θ) and water vapour mixing ratio (q) should with time become equal to the surface values.

The atmospheric boundary layer over the ocean is capped by stable stratification at around 1-2 km and the winds can be strong.

A radiative cooling was introduced and saturation mixing ratio and saturation vapour pressure decrease with height leading to some condensation.

References

• PowerPoint Presentation Peter Taylor