4mm.

0.5 mm.

2mm.

1mm.

The movement of warm air under cold air.

Terrestrial radiation on a clear night with little wind.

Warm air being lifted rapidly aloft, in the vicinity of mountainous terrain.

Heating of the air by subsidence.

FL 100

FL 390

FL 180

FL 160

The pressure gradient force moves the air towards the low pressure, but surface friction starts to pull the air anticlockwise, eventually causing the wind to blow parallel to the isobars with the low pressure positioned downstream to the left.

An air parcel initially at rest will move from high pressure to low pressure because of the coriolis force, but asthe air moves it is deflected to the right and is eventually balanced by the pressure aradient force.

As the air starts to move and is accelerated by the pressure gradient force, it is increasingly deflected to theriaht by the coriolis force until both forces are balanced and opposite to each other.

As a surface pressure difference begins, air will start to move towards the lower pressure. As the wind gains speed the pressure gradient force deflection increases to the right until it equals the coriolis force and the

due to the transfer of latent heat into an adjacent heat sink.

that is best achieved by very slow processes to foster heat exchange.

of an expanding volume of air without heat exchange with its surroundings.

of a volume of air gained by the compression of the respective volume.

low atmospheric pressure, rotating clockwise in the southern hemisphere, counter-clockwise in the northern hemisphere.

high atmospheric pressure, rotating clockwise in the southern hemisphere, counter-clockwise in the northern hemisphere.

low atmospheric pressure, rotating clockwise in the northern hemisphere, counter-clockwise in the southern hemisphere.

high atmospheric pressure, rotating clockwise in the northern hemisphere, counter-clockwise in the southern hemisphere.

This is due to changing wind directions on approach

The airfield is most probably situated near water (on the seaside).

This is typical for northern hemisphere.

This is typical for southern hemisphere.

ratio of the vapour pressure of a sample of air to the saturation pressure at the existing temperature.

temperature at which the pressure exerted by the surroundings upon a liquid is equalled by the pressure exerted by the vapour of the liquid.

temperature at which moisture in the air will condense as a layer of frost on any exposed surface.

temperature at which the vapour present in a sample of air would just cause saturation.

greatest at 60°N.

greatest at 40°N.

the same at all latitudes.

least at 50°N.

Cirrostratus

Stratus

Stratocumulus