Temperature Terminology & stuff Flashcards
High specific heat capacity
Holds heat in. Takes long time to heat & long time to cool.
E.g. water
Inversion
Increase in temperature, higher up you go.
Isothermal layer.
Constant temperature layer. Altitude altitude, but same temperature.
E.g tropopause
Thermal inertia
Speed at which an object takes to change its temperature in accordance to that of its surroundings.
HOW LONG DOES IT RESIST.
Water has high thermal inertia.
Atmospheric pressure is (as described by oana) “the force… ?”
The force of the mass of the gas above
Temperature & water vapour.
Colder temp=
Warmer temp=
Less water vapour
More water vapour
Mid latitude degrees:
30⚫️ to 60⚫️ latitude in both hemispheres
Ozone O3
Above 30km
Absorbs short wave UV
Jet streams come from where there’s
Folds / breaks in tropopause
Density lapse rate MSL: 75%: 50%: 25%:
1.225kgm^3
10,000
22,000
40,000
Actual pressure lapse rate
H =96T/P
Height change in ft per hPa
ISA pressure lapse rate
1 hPa per 27ft up to 18,000
Then
1 hPa per 50ft from 18,000ft +
What’s used to measure upper air temperature?
& surface air temperature?
A radiosonde (balloon thing). A Stevenson screen, at 1.2m above ground
Convection. Rising air creates up currents called:
Thermals
Diurnal
Variation of surface temperature between day & night
Two ways to measure pressure?
Barometer => mercury up a tube
Simple aneroid barometer ‘aneroid wafers’
Altimeter is set at…
ISA pressure
Isobars
Areas where pressure is the same. The weird kinda circular shapes on a contour chart.
Pressure gradient force
PGF
Difference between each isohype.
Strong PGF = highwinds.
Static pressure is
Pressure caused by effect of gravity on mass of air
Dynamic pressure
Kinetic energy per unit volume
Warm air to cold air =
NOT GOOD.
NEARER TO GROUND.
Isohype
The lines of the isobars (the weird kinda circular shape things). Found on a contour chart.
Outside Pressure reading for altimeter enters through the
Static port.
QFE
pressure measured at airfield
QNH
Pressure calculated using ISA lapse rate
QFF
Pressure calculated using actual pressure lapse rate
SPS (standard pressure setting)
1013 hPa
Regional pressure settings (RPS)
Average QNH across large area.
True altitude
Legitimate a/c altitude above sea level
In formula:
Pressure correction - temperature correction
Indicated altitude
Whatever altitude you’ve got on your altimeter
Pressure correction formula
TA=IA +27 (Pressure datum - subscale)
QFE, QNH, QFF. the pressure
You’ve put in
Dial on altimeter
Thickness
T
Height between airport to aircraft indicative altitude / 1000
(Indicative altitude might height from MSL. So bear in mind what elevation the airport is on.
As will need to take the airport elevation away fro, indicated altitude.)
Temperature correction
4 x T x ISA dev
Bernoulli effect=
Increased air flow = reduction in static pressure.
