MET Flashcards
What percentage of accidents are weather related?
About 28%
Unit of measurement: Wind - Direction and speed
Degrees and knots - kt
Unit of measurement: Horizontal vis/RVR
Kilometres or meters - km/m
Unit of measurement: Vertical vis & Cloud base
Feet - ft
Unit of measurement: Cloud coverage
Octas - 8th
Unit of measurement: Pressure
Hectopascal - hPa
Unit of measurement: Temperature + relative humidity/dew point
Degrees Celsius - °C
Precipitation Intensity
Intensity (light, moderate, heavy)
Unit for density?
Kilogram per cubic meter - kg/m³
Where can meteorological services for internation air navigation be found?
ICAO - Annex 3
In what order is the information in a METAR given?
Wind, Visibility, Wx (Weather), Clouds, Temp./Dew point, Pressure, TREND/RMK
Name the meteorological authorities in order
WAFC -> VAAC -> National Met. Authority (DMI) -> MWO (Aerodrome) -> Aerodrome Reporting Office (ARO)
Who sends out METARs?
METAR (MWO/ARO)
Where are the WAFCs located?
London and Washington
Danish MWOs
DMI Copenhagen = Copenhagen FIR
Kangerlussuaq = Søndre Strønfjord FIR
What must MWO prepare and supply?
SIGMETs, AIRMETs and possibly volcanic activity and radioactive materials to its associated ACC/FIC
Aerodome and meteorological offices general functions
- Prepare/obtain forecast of local conditions
- Maintain a survey of current local conditions
- Provide briefing and consultation
- Exchange meteorological information
Name some of the origins of meteorological info
- Airport equipment
- Weather radars
- Satellites
- Aircraft observations
- Wind profilers
What are the interval of octas with the following cloud base indiations FEW, SCT, BKN and OCV?
FEW = 1-2
SCT = 3-4
BKN = 5-7
OCV = 8
CAVOK criterias
- Visibility ≥ 10km
- No CB og TCU
- No cloud below 5000’ og MSA (Whichever is the greater)
- No significant weather at or in the vicinity of the aerodrome
ISA(international standard atmosphere) criteria
- QNH: 1013,25 hPa
- Temperature: 15°C
- Density: 1,225 kg/m³
- No water vapor
- Pressure lapse rate: 1 hPa per 27ft
- Temperature lapse rate: 1,98°C per 1000ft
3 conditions that lower density?
Hot - rise in temperature
Humid - rise in relative humidity
Height - altitude(pressure)
3 requirements for the development of thunder cells?
Vand, Instabilitet og Trigger
Stages of af thunder cell?
Growing, Mature og Dissepating
Characteristics of the growing stage
- Cummulus
- Tilstedeværelse af trigger (processen er startet)
- Kraftig vertikal opdrift
- TCu er slutningen af growing stage
- Stadiet varer ca. 30 min.
Characteristics of the mature stage
- CB
- Både vertikal op- og neddrift af vind
- kraftig bygeregn eller hagl
- Ved nedbør trækkes kold luft nedad (micro- /macroburst) og øger instabiliteten
- Stadiet varer ca. 30 min.
Characteristics of the dissepating stage
- Regnet tør
- Stoppet af tropopausen (ambolt)
- Kan regenere (ved tilførsel af vand) og slutte sig sammen med andre CB’er (supercelle)
- Stadiet varer op til flere timer.
Klassifikation
- Air masses - Polar maritim luft flyttes og opvarmes over land (konduktion)
- Frontal - Varm og fugtig luft presses op af koldfront (hyppig i DK)
- Orographic - Varm og fugtig luft tvinges op af bjerge o.lign.
- Insolation - Kraftig lokal opvarmning af land
Hazards associated with CB’s
- Turbulence
- Hail
- Icing
- Lightning
- Static electricity
- Windshear
