Chapter 12: Weather Theory Flashcards
What is the composition of the Earth’s atmosphere?
78% nitrogen, 21% oxygen, 1% other gases (e.g., argon, carbon dioxide).
What is the troposphere?
The lowest layer of the atmosphere where most weather occurs, extending up to 20,000 feet over poles and 48,000 feet over the equator.
What is the lapse rate in the troposphere?
Temperature decreases by 2°C per 1,000 feet of altitude.
What is atmospheric circulation?
The movement of air around the Earth due to uneven heating of its surface.
What is the Coriolis force?
A force caused by the Earth’s rotation that deflects winds to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
What is a temperature inversion?
A condition where temperature increases with altitude, trapping weather and pollutants below.
What is relative humidity?
The percentage of moisture in the air compared to the maximum amount it can hold at that temperature.
What is dew point?
The temperature at which air becomes saturated and condensation occurs.
What are the four methods air reaches saturation?
- Cooling by contact with a cold surface
- Mixing warm and cold air
- Cooling at night
- Lifting of air in the atmosphere
What are the three basic cloud types by shape?
- Cumulus: Heaped or piled clouds
- Stratus: Layered clouds
- Cirrus: High, wispy clouds.
What are low, middle, and high cloud ranges?
Low: Up to 6,500 feet
Middle: 6,500 to 20,000 feet
High: Above 20,000 feet.
What are cumulonimbus clouds?
Clouds with significant vertical development, often producing thunderstorms, hail, and turbulence.
What is the primary hazard of frost on an aircraft?
It disrupts airflow over the wings, reducing lift and increasing drag.
What is the life cycle of a thunderstorm?
- Cumulus stage: Updrafts dominate.
- Mature stage: Rain begins, with updrafts and downdrafts.
- Dissipating stage: Downdrafts dominate.
What is a microburst?
An intense downdraft in a small area, with winds up to 6,000 feet per minute and durations of 5-15 minutes.
