WEATHER THEORY Flashcards
Composition of the Atmosphere
78% Nitrogen, 21% Oxygen, and 1% trace gases
Atmospheric Circulation
The uneven heating of earths surface
Atmospheric Pressure
Atmospheric pressure decreases by 1” hg for every 1,000 ft of altitude gain.
measurement of atmospheric pressure
29.92 inches of mercury (inHg) or 1013 millibars (mb). 1 inHg = 34 mb. ST temp: 15°C (59°F)
Wind Patterns
Flow of air from areas of high to low pressure
Coriolis Force
Force created by Earth’s spin, deflects air to the right
Convective Currents
uneven heating of localized air
Atmospheric Stability
Ability to resist vertical motion
Inversion
A layer of warm air above cooler air
Moisture and Temperature
The amount of water vapor and heat in the air
Relative humidity
The amount of moisture in the air compared to the maximum it can hold.
Temperature/Dew Point Relationship
The difference between the air temperature and the dew point.
Saturation
The point at which the air can’t hold any more water vapor.
Dew and Frost
Water droplets or ice crystals formed on surfaces due to cooling.
Fog
A cloud that touches the ground
Clouds
Visible masses of water vapor in the sky
Ceiling
Height of the lowest cloud layer.
Visibility
Distance you can see clearly
Precipitation
Water falling from the sky
Air masses
Large bodies of air with similar temperature and humidity
Fronts
Boundaries between different air masses
Warm front
A warm air mass replacing a colder one
Cold front
A cold air mass replacing a warmer one
Stationary front
A front that isn’t moving