PPL Met - Fog DONE

Define fog.

• cloud below 500ft

• saturated air than originated as BR

• cloud that forms on the surface of the land

• cloud on the surface

What are the requirements for fog to form? Choose all that apply.

• cooling process

• adequate supply of moisture

• a warm surface

• availability of condensation nuclei

What are the two main types of fog?

• valley, advection

• radiation, advection

• frontal, radiation

• convection, radiation

How does radiation fog form?

• moist air is transported over a cooler surface

• moist cold air transported over a warm surface

• as the surface cools the air above is cooled through conduction

• warm front rain saturated cooler air below

The development of radiation fog depends largely on:

• the amount of solar radiation encountered during the day

• the ability of terrestrial radiation to escape

• the frequency of the long wave radiation emitted from the earth

• the ability of the wind to transfer a moist air mass

Fog requires _____, without it _____ will develop

• condensation nuclei, cloud

• rain, frost

• cold surface, rain

• wind, dew

When will dew turn to frost?

• when temperature falls below zero

• when wind is <2kts

• when cloud cover prevents solar radiation

• the air has a relative humidity of >100%

Which statement is incorrect in regards to radiation fog?

• fog is more likely when the surface air is stable

• if air is dry, it will have a high dew point therefore fog will not develop

• if wind is too strong low cloud could form instead

• fog is more likely with a clear sky

Why is a light wind required for radiation fog to develop?

• so the moist air mass can be moved over the cooler surface

• so the rate of evaporation reduces and condensation is more likely

• so the influence of the cold surface can spread to a thicker layer

• so the mixing of air can encourage the dew point to increase

Why is radiation fog is more likely in anticyclonic conditions? Choose all that apply.

• generally clear skies

• stable ST cloud will lower to form fog

• generally light winds

• stable surface air