Atmosphere
ThermosphereMesosphere- Stratosphere: Upper level, temperature constant
- Tropopause:
- Boundary layer, Avg 36090ft, -56.5°C
- at equator: 55000ft, -75°C
- at polar: 25000ft, -45°C
- Troposphere:
- Half the mass of atmosphere is in the lower 5km
Lapse Rate
|
|
per 1000ft
|
per 100m
|
| Absolute instability
|
>3°
|
|
| Dry Adiabatic Lapse Rate
|
3°
|
1°
|
| conditionally stable
|
2-3°
|
|
| Average Environmental Lapse Rate (ISA) 15° @ MSL
|
1.98°
|
0.65°
|
| Saturated Adiabatic Lapse Rate (Central Europe)
|
1.8°
|
0.6°
|
| stable
|
<2°
|
|
|
|
|
|
| Dew point
|
0.5°
|
|
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
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
- Col: saddle point/neutral point
- Convective weather:
- Thunderstorms, hail, tornados, wind gusts, heavy showers, lightning strikes
- Low pressure travelling in summer: between 45° - 70°
- Veering:
- Backing:
Air Masses
| prefix
|
suffix
|
| A = Arctic
|
m = maritime
|
| P = Polar
|
c = continental
|
| T = Tropical
|
|
| E = Equatorial
|
|
Clouds
- 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
Fog
- Radiation fog: at night/early day, when the ground cools. wind <5kt
- Advection fog: warm, moist air over cooler ground/sea below, 10-15kt, can withstands 25kt winds
- Frontal fog: ahead of warm front
Icing
Other
- CAVOK: vis 10km+, no clouds below 5000 above GND
METAR / TAF Abbreviations
METAR: every 30min at :20 and :50