Flashcards in 2.3 Weather processes and phenomena Deck (29)
Adiabatic lapse rate
Change of temperature caused by the air changing internally. i.e rising and falling in height
Change in temperature of a parcel of air caused by its ascent or descent. Changes are internal.
It is formed by warm air flowing over a cold surface, being chilled, reaching dew point , and condensation taking place, close to the ground's surface.
Large body of air with relatively similar temperature and humidity characteristics
Measurement in height usually given in meters above sea level.
Water vapour condensed into millions of minute water particles that float in masses in the atmosphere.
Altitude at which relative humidity is 100 percent, when clouds form.
When the ELR is lower than the DALR (dry adiabatic lapse rate) but higher than the SALR (saturated adiabatic lapse rate). The air in unstable so dew point is reached.
Region of low atmospheric pressure.
Precipitation in the form of moisture that collects on the ground.
How is dew formed?
It is formed after temperature of the ground has fallen below dew point of the air in contact with it.
Temperature at which relative humidity is 100 percent
Environmental lapse rate (ELR)
Normal decline of temperature with altitude; usually about 6/1000m
Process by which a liquid if transformed into a gas.
Cloud at ground level, composed of water vapour that has condensed on particles of dust in the atmosphere.
Boundary between a warm air mass and a cold air mass that results in frontal (cyclonic) rainfall
Measure of the amount of moisture in the air.
How much moisture there is in the air
How much moisture air at an specific temperature can hold
Refers to unstable atmospheric conditions (rising air) likely to cause cloud formation and precipitaion
Rate of change of atmospheric factors (temperature and humidity) with changing altitude
Low cloud caused by condensation of water vapour in lower part of the atmosphere. (less thick than fog)
Orographic (relief) rainfall
Rainfall that occur when an airstream is forced to rise over a mountain range
Fog forms on clear, calm nights when the land surface loses heat capacity the air above is cooled to below dew point and condensation takes place.
Leeward side of hills, which has a relatively light rainfall compared to the windward side.
Refers to pressure conditions; air is unable to rise above a low level, calm , dry conditions.
Usually carried by intense heating of ground surface during the summer.
Dry adiabatic lapse rate (DALR)
Adiabatic cooling and warming in dry unsaturated air occurs at around 10/km