Atmosphere & Weathers Flashcards
Energy available at the surface =
Incoming solar radiation - (reflected solar radiation + surface absorption + sensible heat transfer + long wave radiation + latent heat transfers)
Albedo
Proportion of energy that is reflected back to the atmosphere
Sensible heat transfer
Movement of parcels of air into and out of the area being studied
Night time energy budget - 4
Latent heat transfer- Condensation
Absorbed energy returned to Earth (sub -surface supply)
Earth radiation
Sensible heat transfer
Absolute humidity
Amount of water in the atmosphere
Relative humidity
Water vapour present expressed as percentage of maximum amount of water vapour air at that temperature can hold
Condensation nuclei
Ie dust and salt
Needed for fog and mist to form
Advection fog
Warm air flows over a cold surface
Eg. Warm air from the Gulfstream passes over waters of Labrador current near the Grand Banks of Newfoundland
Radiation fog
Ground loses heat at night by long wave radiation
High pressure conditions ie clear skies
Dew
Condensation on a surface
Temperature inversions
Relative increase in temperature with height in the lower part of the atmosphere
Specific Heat Capacity
The amount of heat needed to raise the temperature of a body by 1*C
Coriolis Effect
Deflection of moving objects caused by the easterly rotation of the Earth
Adiabatic processes
Processes that relate to the rising and sinking of air
Diabatic processes
Physical mixing of air
Normal / Environmental Lapse Rate
Actual temperature decline with height
- usually 6*C/km
DALR
Dry Adiabatic Lapse Rate
Adiabatic cooling and warming in dry (unsaturated) air
- 10*C / km
SALR
Saturated Adiabatic Lapse Rate
Adiabatic Cooling and warming in saturated air
- between 4C / km and 9C / km
Unstable air conditions
ELR > DALR
Eg. On a hot day when ground layers are heated considerably
Stable air conditions
ELR > DALR
ELR > SALR
Eg . Anticyclone (high pressure conditions)
Conditional Instability
ELR between SALR and DALR
When air is saturated
Anticyclones
Stable high pressure systems characterised by
clear skies
Low wind speeds
Advection fog
Warm moist air flows horizontally over a cooler land or sea surface
Steam fog
Cold polar air meets relatively warm water
Evaporation from the water quickly saturates the air and resulting condensation leads to steaming
Radiation fog
Low lying areas during calm weather
Surface of the ground is cooled at night and cools air above it
Air flows into hollows and is cooled to dew point
Dew point
Temp at which condensation occurs
Daytime energy budget - 6
Incoming solar radiation Reflected solar radiation Surface absorption Sensible heat transfer Long wave radiation Latent heat (evaporation)
