fog & clouds quiz Flashcards
what is fog?
near saturation conditions which forms a cloud close to the ground (RH = 100%)
in what two basic ways does fog form?
- cooling
- adding moisture (by evaporation and mixing)
what are the four types of fog?
radiation
advection
upslope
mixing
what is radiation fog?
- lots of radiational cooling
- no/slight breeze
- can help evaporate & supply moisture
what is advection fog?
horizontal movement at air = advection
warm, humid air to move over a cold surface
what is upslope fog?
sloping terrain lifts air, cooling it adiabatically to its dew point and saturation
what is mixing fog?
warm surface provides enough moisture to saturate a dry air parcel (short-lived)
what are cirrus clouds?
thin, wispy clouds of ice
what are stratus clouds?
horizontally layered clouds
flat appearance
what are cumulus clouds?
vertical development
puffy picture appearance
what are nimbus clouds?
rain (storm) clouds
tinted (grey, black, green)
what are the height factors?
low, mid, high, vertical
what are the appearance factors?
shape, density, color
cirro prefix…
high
>5000m or 16,000 ft
alto prefix…
2000-7000 m
6500-23,000 ft
what clouds extend through all levels of atmosphere?
clouds with vertical development
what are scud clouds?
fractus cloud at low height above ground
often ragged or wispy in appearance
what are mammatus clouds?
- formed by cold air sinking down to form the pockets
- indicate convectively induced turbulence
what are lenticular clouds?
normally develops on the downwind side of a mountain or mountain range
what are nacreous (stratosphere) clouds?
- form in the lower stratosphere over polar regions when the sun is just below the horizon
- ice particles are much smaller than those that form more common clouds
what are nocticulnet (mesosphere) clouds?
- diffuse scattering layer of water ice crystals near the summer polar mesopause
- resemble cirrus clouds
what are the four importances of clouds?
- release heat to the atmosphere
- help regulate energy balance
- provide precipitation for the surface
- indicate physical processes
what are cloud coverages divided into?
8ths
what is used at airports to determine cloud height?
ceilometer
