Chapter 8.4 - Exam Review

Question 1

What does an isobar represent on a MSL MET chart? How are isobars numbered, and at what intervals are they usually drawn (3)?

Answer 1

• Isobars join places of equal MSL Pressure.
• MSL Pressure.
• 2 to 4.

Question 2

Which type of pressure system is indicated when the pressure is increasing towards the centre of the system?

Answer 2

High Pressure/Anticyclone.

Question 3

Which type of pressure pattern is indicated when the isobars are widely spaced and the circles formed by the isobars are of relatively large diameter?

Answer 3

High Pressure/Anticyclone.

Question 4

What is a Col?

Answer 4

An area of neutral pressure between two anticyclones and cyclones.

Question 5

What is a Ridge?

Answer 5

An elongated area of high pressure.

Question 6

In the southern hemisphere, what is the general direction of the wind in an anticyclone?

Answer 6

Anticlockwise.

Question 7

What is the gradient wind?

Answer 7

The wind resulting in the combined effects of Pressure, Coriolis and Centripetal forces.

Question 8

If an observer stands with their back to the wind (in the southern hemisphere), is the higher pressure on their right or their left?

Answer 8

Left.

Question 9

Except for some local phenomenon such as a sea breeze affecting the surface wind, will the gradient windspeed at a particular place normally be (greater/less than) the surface windspeed?

Answer 9

Less than.

Question 10

Briefly describe the relationship between the surface wind direction and the isobars?

Answer 10

The wind blows across the Isobars from a high to a low pressure.

Question 11

Describe the difference between gusts and squalls (2)?

Answer 11

• Gust = A momentary increase in wind speed and usually lasts for only a few seconds.
• Squall = A sudden, increase in the wind speed which lasts for several minutes, then dies away.

Question 12

Describe the difference between backing and veering in terms of wind direction (2)?

Answer 12

• Backing = Wind directions changes in an anticlockwise direction.
• Veering = Wind direction changes in a clockwise direction.

Question 13

What effect does surface friction have on the speed and direction of the gradient wind?

Answer 13

Decreases the gradient windspeed and changes its direction.

Question 14

What weather phenomenon is normally associated with a strong pressure gradient (strong winds/light and variable winds)?

Answer 14

Strong Winds.

Question 15

At what time of day is it more usual for a sea breeze to commence? When is it likely to be at its strongest?

Answer 15

Early Afternoon (1500 to 1600).

Question 16

At what time of day is a land breeze likely to be at its strongest (around sunrise/late afternoon)?

Answer 16

Around Sunrise.