Lesson 302 Formation Of Clouds And Weather Flashcards
List the 5 reasons why clouds are important in meteorology.
FEAPA
Forms of weather Effects on the heat budget Atmospheric processes Precipitation formation Actual conditions
State the two main processes in the atmosphere that produce cloud
Cooling
Evaporation
What are the two main processes of cooling?
Diabatic cooling
Adiabatic cooling
Define diabatic process.
One in which there is an exchange or transfer of heat across the boundaries of a parcel i.e.something warm heats up something cold or vice versa.
List the three common types of diabatic cooling in the atmosphere.
RAM
Radiation
Advection
Mixing
Generally ________ wind will favour fog formation whereas ________ wind will lead to the formation of stratus.
Light
Moderate
An adiabatic process is one in which there is ___________________ across the boundaries of a parcel and heating or cooling occurs through ________ or ________ of the parcel itself due to __________ change.
No exchange of heat
Compression or expansion
Pressure
List the five synoptic situations where large scale dynamic lift will often produce clouds and weather.
VIJAR
Vicinity of low pressure centres and troughs Regions of baroclinic development In advance of warm fronts and TROWALs Ahead of upper short wave troughs Jet stream maximums (RELE)
What is the main cause for the formation of cloud in the boundary layer?
Low-level convergence generating upward vertical motion
List the broad scale processes used to asses the presence of boundary layer clouds and precipitation:
LUSLEC
Low level convergence Upslope/onshore flows Surface winds >15 KT Large areas with moist surface conditions Evaporation of precipitation Cooling by advection/conduction
Wind speed during night time cloud formation will be the determining factor on type and thickness. State the speeds and type of cloud formed.
>
> 10 KT = SC
<10 KT = FG / ST
The main process for dissipating boundary layer cloud during the day is initiated by ________ _________.
Solar heating
Explain how upslope boundary layer clouds and precipitation are formed.
A flow of air moving over increasingly higher ground will be lifted adiabatically. Whether or not condensation will occur due to the upslope terrain will depend on the moisture content of the air.
Explain how boundary layer clouds are lowered in precipitation.
Precipitation causes an increase in moisture in the lower levels of the atmosphere due to evaporation, resulting in a higher dew point. The evaporation process the cools the air through latent heat storage resulting in lower temperatures. An increasing dew point combined with a decreasing temperature means the DP spread decreases causing the cloud ceiling to lower.
