Pressure Systems and Wind Flashcards
The force per unit area exerted by the weight of the air lying above that level.
Atmospheric Pressure
What are the 2 common methods of measuring pressure?
- Digital Barometer
- Aneroid Barometer
What are the units used for pressure in aviation?
- Inches of Mercury (inHg)
- Hectopascals (hpa)
Type of barometer that measures the atmospheric pressure electronically and displays the results digitally.
Digital Barometer
Type of barometer that is a partially evacuated flexible metal cell that contracts with increasing pressure and expands with decreasing pressure. The change is registered on a scale by means of a needle and coupling mechanism.
Aneroid Barometer
The weight of the air above the airport that is measured.
Station Pressure
The station pressure plus the weight of the fictitious column of air between the station and mean sea level.
Mean Sea Level Pressure
Lines drawn on a Surface Weather Map joining places of equal MSL Pressure.
Isobars
What is the interval between Isobars on a Surface Weather Chart?
4 Hectopascals
Areas of MSL pressure surrounded on all sides by higher pressure.
Low Pressure
What are other names for Low Pressure areas?
- Depressions
- Cyclones
The curvature of isobars to the left if you were to stand with lower pressure to your left.
Cyclonic Curvature
Areas of pressure surrounded on all sides by lower pressure.
High Pressure
What is another name for High Pressure areas?
Anticylones
The curvature of isobars to the right if you were to stand with lower pressure to your left.
Anticyclonic Curvature
Elongated areas of low pressure with the lowest pressure along the line of maximum cyclonic curvature.
Troughs
Elongated areas of high pressure with the highest pressure along the line of maximum anticyclonic curvature.
Ridges
Neutral areas between 2 highs and 2 lows.
Cols
The rate of rise or fall of pressure at a particular location.
Pressure Tendency
The force that causes air to move from high pressure to low pressure.
Pressure Gradient Force
What determines the strength of the Pressure Gradient Force?
Pressure difference over the area
Isobars that are spaced closely together are called what?
Steep or Strong