101-4 Wind Flashcards
Convection
Rising air
Hot air rising - convective activity
Advection
Horizontal movement of air
Advection fog - wind + fog
Uneven heating of air by contrasting surface temps
Pressure Gradient Force
(PGF)
-force that drives winds across isobars & contours from H to L pressures
-difference in pressure stems from diff. In temps (i.e. the greater the temp difference the greater the PGF)
Coriolis Force
- Deflection force winds due to earths rotation
- To the right in the Northern Hem.
- Surface friction decreases wind speed & the CF ( little affect above 2000)
- CF has least effect on wind direction @ equator (strongest at poles)
US high alt winds are westerly
Wind shear
Rapid change of wind speed/direction over a relatively short distance, time or altitude
Vertical Wind Shear
(VWS)
Change in wind speed / change of altitude
If VWS > or equal to 6kts/1000’ = moderate turb
If VWS > or equal to 10kts/1000’ = severe turb
Horizontal Wind Shear
(HWS) during cruise
Change of wind speed / distance
If HWS > or equal to 18kts/150nm = moderate
If HWS > or equal to 40kts/150nm = severe
KATL @ FL300 has a wind speed of 50kts
KATL @ FL340 has a wind speed of 82kts
What type of turbulence?
8kts = moderate turbulence