Met Flashcards
The sphere closer to the earths surface us
Troposphere
The tropopause is (higher/lower) and (warmer/colder) over the equator than at poles
Higher
Colder
A trough is an extension from a …
Low
A ridge is an extension from a …
High
Main elements of an ISA
Sea level pressure 1013.2 hPa
Air temp at sea level 15C
Temp lapse rate of 1.98C/1000ft
Temp above 36090ft constant -56.5C
What is pressure lapse rate
A given reduction of pressure with height
Pressure lapse rate is higher or lower in cool air
Higher, as cool air column particles are closer together and therefore column is shorter, so height increase will have greater impact on pressure
What is a col
A neutral area between two highs and two lows. Wind will be calm
What is pressure gradient
The change in pressure per horizontal distance
Increased temp does what to density
Decreases
Dew point defined
Temperature at which air becomes saturated
When temp drops below dew point what occurs
Condensation
When moisture is added to air, it’s density will
Decrease
As temp decreases, RH goes up until dew point reached, then condensation takes place
.
When air temp reduces, what happens to RH and DPt
RH goes up
DPt not affected
When air temp increases, what happens to RH and DPt
RH goes down
DPt not affected
When water vapour increases, what happens to RH and DPt
RH goes up
DPt goes up
When water vapour decreases, what happens to RH and DPt
RH goes down
DPt goes down
When ice turns to vapour
Sublimation
When vapour turns to ice
Deposition
Height of tropopause over equator
60,000ft
Height of tropopause over poles
30,000 ft
Temp constant with height called
Isothermal layer
Temp increase with height called
Inversion
RH% = 100-5(temp-dew pt)
.
Land veer
30% & 2/3 reduction
Sea veer
10% & 1/3 reduction
DVD
ABI
Descend, veer, decrease
Ascend, back, increase
Dry adiabatic lapse rate
3C/000ft
Saturated adiabatic lapse rate
1.5C/000ft
Sea breeze characteristics
10-15 kts 25-40km inland 2-3000ft Fair weather cumulus Wind sheer at top of sea breeze
Land breeze characteristics
3-4 kts
No cloud
Katabatic wind characteristics
Light
Not turbulent
From descending cold wind on mountainous terrain
Settling cold air can cause fog
Anabasis wind characteristics
Go up - opposite to katabatic
Light
Gusts defined
Temp increase in wind speed from terrain or obstructions
Squall defined
Rapid increase >16kts to 22kts for > 1 minute
Fohn wind
A substantial mountain range Wind at right angles High moisture content of approaching air Dry, warm and gusty On dry side, cloud base at dew point
Mountain waves (MTW)
Moderate to severe turbulence
Possible rotor action
Strong down draughts
Reporting cloud - FEW
1-2 oktas
Reporting cloud - scattered SCT
3-4 oktas
Reporting cloud- broken BKN
5-7 oktas
Reporting cloud- overcast OVC
8 oktas
Height of high cloud
> 17000ft
Height of Middle cloud
7-17000 ft
Height of low cloud
<7000ft
Clear ice conditions
Supercooled water 0 to -15C
Small part freezes on impact and rest runs back
Cumuliform
Rime ice conditions
Temp <-15C
Greater amount freezes on impact
Stratiform
Freezing rain conditions
Warm rain falls through colder air
Typical on warm fronts
Different freezing levels
Carb icing conditions
25C to -15C
Abbreviation for mist
BR
Abbreviation for drizzle
DZ
Abbreviation for smoke
FU
Abbreviation for shallow
MI
Abbreviation for mountain waves
MTW
Abbreviation for no cloud detected
NCD
Abbreviation for dust
PO
RVR
Runway visual range
Abbreviation for snow
SN
Abbreviation for partial/patches
PR