Chapter 4 Flashcards
The difference between Pressure Altitude and True Altitude.
D-Value
A sudden increase in wind speed by a magnitude of 16Kts or greater to a sustained speed for a period of 1 minute.
Squall
Reported when there is at lease a 10Kts variation.
Gust
The movement of air that results from differential heating.
Thermal Circulation
A VECTOR QUANTITY of wind.
Wind Velocity
Wind blow in the counterclockwise direction.
Anti-Cyclonic Flow
The force that resists the relative motion of two bodies in contact.
Friction
The MAGNITUDES of Wind Velocity.
Wind Speed
The resistance of the atmosphere to the relative motion of the aircraft.
Drag
The maximum instantaneous wind speed greater than 25Kts since the last hourly observation.
Peak Wind Speed
Can only happen when the wind is already blowing.
Geostrophic Balance
Produces the centripetal acceleration.
Centrifugal Force
Always acts 90 degrees to the right of the wind, looking downstream.
Coriolis Force.
The direction FROM which the wind is blowing.
Wind Direction
Wind blow in the clockwise direction.
Cyclonic Flow
The difference in pressure between two points divided by the distance between the two points.
Pressure Gradient Force
The resistive force that arises from a skin friction and turbulence near the earth’s surface.
Surface Friction
A transition zone between large surface frictional effect near the ground and negligible effect about the boundary layer.
Boundary Layer
