Projects:EASA PPL/Meteorology

• Stratosphere: Upper level, Temp constant
• Tropopause:
  • Boundary, Temp is higher in polar regions, 36090ft, -56.5°C
  • at equator: 55000ft, -75°C
  • at polar: 25000ft, -45°C
• Troposphere:
  • Half the mass of atmosphere is in the first 5km

Lapse rate

	per 1000ft	per 100m
-> Absolute instability	>3°
Dry Adiabatic	3°	1°
-> conditionally stable	2-3°
Average (ISA) 15° @ MSL	1.98°	0.65°
Saturated (Central Europe)	1.8°	0.6°
-> stable	<2°
Dew point	0.5°

• Convective weather:
  • Thunderstorms, hail, tornados, wind gusts, heavy showers, lightning strikes
• Altimetry:
  • Pressure altitude: Indicated altitude at 1013.25 hPa setting
  • Density altitude: pressure altitude corrected for non-ISA temperatures (120ft per 1°C change from ISA)
  • QNH: ..N.. nautical
  • True altitude:
  • Wind on hPa - Wind on height
  • Wind off hPa - Wind off height
  • High to low - beware below
  • Low to High - up in the sky
  • 1) Correct altitude for pressure: 1hPa = 27ft
  • 2) Correct altitude for Temp: 1% per 2.5°C change from ISA
    • colder: indicated alt minus offset / warmer: indicated alt plus offset
  • Col: saddle point/neutral point
• Low pressure travelling in summer: between 45° - 70°
• Clouds:
  • AC - Altocumulus
  • AS - Alsostatus
  • CB - Cumulonimbus
  • CC - Cirrocumulus
  • CI - Cirrus
  • CS Cirrostratus
  • CU - Cumulus
  • NS - Nimbostratus (moderate to severe icing)
  • SC - Stratocumulus
  • ST - Stratus
  • Altocumulus lenticularis: mountain wave cloud, strong wind at right angle to the ridge, stable air
• Wind
  • Mountain-valley:
    • Katabatic: at night down from the mountains
    • Anabatic: up the mountain by day
  • Land-breeze: From land-to-water, during the night, weaker than sea-breeze
  • Sea breeze: From the sea to land, during the day
  • pressure gradient: diff between high and low
  • straight isobar: pressure gradient force + coriolis force
  • curved isobar: gradient wind: pressure gradient force + coriolis force + centrifugal force