High - Low pressure systems

Question 1

In a low pressure system, convergence at the surface is caused by

Answer 1

Frictional forces

Question 2

What is a cold air drop? What chart would you use to find one?

Answer 2

A low pressure area with colder air compared to its surroundings. It can be found on upper contour charts

Question 3

Divergence over a uniform surface is caused by:

Answer 3

Frictional force + anticyclonic curvature of the isobars

Question 4

Area of thermal low pressure is formed by:

Answer 4

A temperature rise in an area in relation to the environment

Question 5

How do you recognise a cold air pool?

Answer 5

As a low pressure area aloft (e.g on the 500 HPA chart)

Question 6

What weather is encountered during summer, over land, in the centre of a cold-air drop?

Answer 6

Showers and thunderstorms

Question 7

How long does a typical frontal depression last in Europe?

Answer 7

7-10 days

Question 8

System that REDUCES in intensity with increasing height must be :

Answer 8

Cold and high pressure as it is concentrated at lower levels

Question 9

What happens in a trough near the surface in terms of horizontal and vertical air movement?

Answer 9

Convergence and widespread ascent

Question 10

Under anticyclonic conditions in the northern hemisphere, with curved isobars the speed of the gradient wind is :

Answer 10

Greater than the geostrophic wind