Meteorology Flashcards
What is the validity period of a SIGMET
4 hours
at what windspeeds will an aerodrome SIGMET be issued
20G28KT or 25G37KT depending on aerodrome requirements
At what visibility in fog will an aerodrome SIGMET be issued
below 600m
how often are windshear SIGMETs updated
every minute
how many Volcanic Ash Advisory Centres are there?
9
what do Regional Specialised Meteorological Centres (RSMC) do, and how many are there
they Monitor, Track and advise on tropical revolving storms, there are 6 of them
how often is a VOLMET updated
every 30 minutes
on what frequency bands are VOLMETs broadcast
HF and VHF
in an ATIS, are winds given in TRUE or MAG
MAG
in the UK, how many times is FORM 214 issued in a 24 hour period
4 times
What is the pressure at 5000 ft ISA
850 hPa
What is the pressure at 18000 ft ISA
500 hPa
at what altitude is density constant with latitude
26,000 ft
how long does the influence of a temporary cold anticyclone last?
roughly 24 hours
what are the features of a col in summer and winter
thunderstorms in summer, fog and poor vis in winter
what is the average lifetime of a frontal pressure system
10 - 14 days
at what flight level is the pressure 250 hPa
FL 340
at what flight level is the pressure 200 hPa
FL 390
at what latitudes does the STJ occour
NH: 25 - 40 degrees in winter, 40 - 45 degrees in summer
SH: 25 - 30 degrees
at what latitudes does the PFJ occour
40 - 65 degrees N, 50 - 55 degrees S
by what distance does the PFJ lag a cold front
200 nm
by what distance does the PFJ lead a warm front
400 nm
what is the range of low clouds
sfc - 6500 ft
what is the range of mid level clouds
6500 ft - 23000 ft
what is the range of high level clouds
16500 ft - 45000 ft (tropopause)
at what height is a stevenson screen and what does it contain
4ft agl, and contains a hygrometer and/or thermograph
what is the typical absolute humidity at the equator
25 g / cubic meter
what is the typical absolute humidity at the poles
0 g / cubic meter
what is another name for a hygrometer
a psychrometer
what is the DALR
3 degrees / 1000 ft
what is the SALR
1.8 degrees / 1000 ft, though it is slightly greater in cold air, and slightly less in hot air
what is conditional stability
It does not exist. conditional INstability is where DALR>ELR>SALR
what is vertical windshear measured in
knots per 100 ft
what is horizontal windshear measured in
knots per 1000 ft
what is the depth of the friction layer
2000 ft - 3000 ft
is the friction layer thinnest during day or night
night, as there is no convective turbulence, only mechanical turbulence
what fluctuations in IAS and g might light turbulence cause
5 - 15 kt, <0.5g
what fluctuations in IAS and g might moderate turbulence cause
15 - 25 kt, 1.0 g - 0.5 g
what fluctuations in IAS and g might severe turbulence cause
> 25 kt, >1.0 g
what is the diameter of a microburst
<5 km
what is the duration of a microburst
1 - 5 mins
what is the transition level?
the lowest usable flight level above the transition altitude
what is a squall
a sudden increase in wind speed lasting over a minute
what is a gale
Where wind speeds exceed 33 kt, or gusts exceed 42 kt
what windspeed defines a hurricane
where winds exceed 63 knots
at what height is the wind vane and anemometer positioned
10 m AGL
what is the equation for coriolis force
CF = 2 Ω ρ V sin θ
at what height does the geostrophic wind exist
above the friction layer (2000 - 3000 ft)
in the northern hemisphere over land, what will the surface wind do in relation to the geostrophic wind
speed reduction of 50%, backing 30 degrees
in the northern hemisphere over sea, what will the surface wind do in relation to the geostrophic wind
speed reduction of 30%, backing 10 degrees
what is the range and speed of a sea breeze
10 - 15 kt, 10 - 15 nm either side of the coast
what is the range and speed of a land breeze
5 kt, 5 nm either side of the coast
what is the typical speed of a katabatic wind
10 kt
what is the typical speed of an anabatic wind
5 kt
