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17 Cards in this Set
- Front
- Back
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What is the atmospheric window?
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Infra-red radiation in the 8 to 11 micron band passes directly through the atmospheric window and is lost to space
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What is a frontal inversion?
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When warm air is forced to rise over cool air
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What are isallobars?
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Lines joining points of equal rate of change of pressure
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What is the formula for 'change of pressure with height'?
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(96 x Mean Temp (Kelvin) ) / Mean Pressure
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What is relative humidity?
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A ratio of the actual water vapour content (WVC) of the air at a given temperature to the maximum amount of water vapour the air could hold at that pressure
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How can relative humidity be changed?
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1. Adding or removing moisture
2. Change air temperature |
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What is a hygrometer?
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A wet / dry bulb thermometer
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What percentage of molecular mass is found in the Troposphere?
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75% of all molecular mass
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Is the tropopause higher over the equator or poles?
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Equator
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What is the average tropopause temperature over the equator and the poles?
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-80 over equator and -48 over poles
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What is the formula to find out pressure variation with height?
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(96 x Temperature (Kelvin))
/ Pressure |
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What is QNH (also known as absolute altitude
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Atmospheric pressure reduced to mean sea level using ISA values.
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What is QFE
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Ambient atmospheric pressure at a given datum, e.g. 0 showing on altimeter
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What is QNE
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1013.25hPa set, Pressure altitude
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What is QFF
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Atmospheric pressure reduced to mean sea level using existing atmospheric values (Synoptic weather charts)
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At what temperature does a mercury thermometer become unreliable? and why?
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Below -36 degrees, the freezing point of mercury
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How far above ground is surface air temperature measured?
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1.5Metres so that free flowing air is measured
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