Weather 1: Weather Theory Flashcards
What is the troposphere?
The layer adjacent to the Earth’s surface
Average height of 55,000 ft. over the equator and average height of 28,000 ft. over the poles
What is the make up of the Earth’s atmosphere?
- 78% Nitrogen
- 21% Oxygen
- 1% Other
What is the average height of the troposphere over the US?
36,000’ MSL
Where does nearly all weather on Earth occur?
In the troposphere
What is the tropopause?
It’s the transition zone between troposphere and stratosphere
What is the relationship between altitude and temperature in the troposphere?
Temperature normally decreases as altitude increases
What is the relationship between altitude and temperature in the tropopause?
Temperature is constant as altitude increases
Where does jet stream winds occur?
Just below the tropopause (in the troposphere)
Atmospheric Pressure
The pressure exerted on a surface, by the atmosphere, due to the weight of the column of air directly above that surface
What are the units of measurement for pressure?
- Inches of mecury (in-Hg)
- Milibars (mb)
Station pressure
The atmospheric pressure measured directly at an airfield/weather station
Sea level pressure
Pressure that would be measured from the existing weather if the station were at mean sea level
Why do all stations report sea level pressure instead of station pressure?
If station pressure were used by everyone then maps would depict reverse topography
Meaning that stations at high altitudes would report lower pressure
What is the primary reason that atmospheric circulation takes place?
Ascending and descending air currents due to heating and cooling of the earth’s surface
Pressure gradient
The rate of pressure change in a perpendicular direction across the isobars