Isobars
Isobars are lines on a weather map joining together places of equal Atmospheric pressure is the weight of air pressing down on us. Air is light but because there is so much of it above us, it exerts a pressure on us. Atmospheric pressure is measured by a barometer. The units used are millibars..
On the map the isobar marked 1004 represents an area of high pressure, while the isobar marked 976 represents an area of low pressure.
Isobars on a weather map
Not only do isobars tell us whether there is high or low pressure but they also tell us about wind:
- When the isobars are closer together the wind is stronger.
- When the isobars are further apart the wind is calmer.
Question
- a) Name one city in the UK experiencing high pressure and one city in the UK experiencing low pressure.
- b) Which city on the map is experiencing the highest pressure?
- c) Name one city out with the UK that is experiencing high pressure and one city that is experiencing low pressure.
- a) Glasgow low, London high
- b) Rome
- c) Madrid or Lyon for high, Trondheim for low