1- On a day in summer with a slack pressure gradient, an airfield on the south coast of England has a surface W/V of 080/06 at dawn. The coast/line is in an East/West direction. The most probable W/V at noon would be:
360/12.
080/18.
180/18.
080/06.
2- The surface wind direction in the Northern Hemisphere is backed from the 2000 ft wind by an average of 30o over land due to:
Friction reducing the wind speed, thus reducing the geostrophic force, allowing the pressure gradient force to pull the wind across the isobars towards low pressure.
The frictional effect at the surface, causing the surface isobars to curve more than those at 2000 ft.
The geostrophic wind only flowing between straight and parallel isobars with an unchanging pressure gradient with time, whereas the surface pressure gradient changes diurnally with surface heating.
The effect of the cyclostrophic force, which is strongest at the surface due to increased curvature.
3- When a Fohn wind occurs:
There are unstable conditions on the downwind side of the mountain.
Air is cooled mainly at the DALR on the upwind side of the mountain and is heated at the SALR on the downwind side.
Windspeed must be at least 15 kt at the surface increasing with height and maintaining direction.
Air is cooled mainly at the SALR on the upwind side of the mountain and is heated mainly at the DALR on the downwind side.
4- The geostrophic wind blows:
Parallel to curved isobars.
When pressure values are changing rapidly.
In a tropical revolving storm.
When geostrophic force and pressure gradient force are equal.
5- A Katabatic wind can result in:
An increase in temperature.
Fog in the valley at night.
Thunderstorms in summer.
Stratus cloud.
6- A strong wind that rises suddenly, lasts for some minutes and dies comparatively suddenly away is called:
A gust.
A squall.
A gale.
A blast.
7- A ravine or valley wind:
Is a wind blowing at increased speed along a valley.
Is a wind blowing from a hill to a valley below.
Is a wind blowing up a hill from a valley.
Is a wind blowing at reduced speed along a valley.
8- Which of the following is true of a land breeze?
it blows only at noon
it blows from land to water
it blows from water to land
it blows by day
9- What characteristics will the surface winds have in an area where the isobars on the weather map are very close together?
Strong and flowing across the isobars.
Very weak but gusty and flowing across the isobars.
Moderate and flowing parallel to the isobars.
Strong and flowing parallel to the isobars.
10- Taking into account the cyclostrophic balance, what will be the intensity of wind (in km/h) if we consider a vortex in rotation of 100 m radius with a variation of 4 hPa per 100 m? (You should consider 1.225 kg/m3 as the density of the air).
200 km/h.
175 km/h.
150 km/h.
65 km/h.
