Facts Flashcards
What’s the most important differences between the phases of water in the atmosphere?
The amount and motion of particles
What are the phase changes of water in the atmosphere?
Evaporation/Condensation
Sublimation/Deposition
What happens to the specific humidity of a parcel as it moves?
It preserves it’s specific humidity
What is water vapour pressure?
A measure of the amount of water vapour in the atmosphere is the pressure that the water molecules alone exert
What is saturation vapour pressure?
The maximum vapour pressure of water at a given temperature
What is the most common measure of humidity?
Relative humidity
What is the dew point?
The temperature to which a packet of air would have to be cooled for water vapour saturation to occur
What device is used to measure humidity
A Hygrometer, sometimes a psychrometer
How do you calculate the depression of a wet bulb?
Dry bulb temp- Wet bulb temp
What does water condense on in the atmosphere?
Condensation nuclei
How does ground fog form?
Cooling below dew point of air in contact with the ground by radiation, often on still, clear nights.
What makes fog more likely?
Evaporation from ground water
How is Advection fog formed?
By moist air being blown over a cool surface which cools the air to dew point.
How is headland fog formed?
Encouraged by the cooling of rising air coming over the headland from the sea.
What are the low clouds?
Stratus, Stratocumulus, Nimbostratus
What are the middle clouds?
Altostratus, Altocumulus
What are the vertically developed clouds?
Cumulus, Cumulonimbus
What are the high clouds?
Cirrus, Cirrostratus, Cirrocumulus
What do cirrocumulus clouds look like?
Small globular masses showing convection cells sometimes rippling lines
What do cirrostratus clouds look like?
Thin veil of high cloud, often presaging worsening weather
What do Altostratus clouds look like?
A grey sheet of cloud, sun weakly visible through it. Typically occurs before rainy weather
What do Altocumulus clouds look like?
Lower, thicker and often more extensive cirrostratus clouds.
What do stratus clouds look like?
A low layer of dark cloud
What are Nimbostratus clouds?
Low rain clouds
