PPL » Meteorology » Weather Maps
8.4 Weather Maps
8.4.2 Identify the following features found on surface weather maps:
8.4.4 Explain the most common weather characteristics of each feature.
Isobars are lines on a weather map, connecting points of equal atmospheric pressure.
(b) anticyclone (“high”);
In the Southern Hemisphere, an anticyclone is an anticlockwise circulation of winds around a central region of high atmospheric pressure,
- It has higher pressure at its center than the areas around it.
- Air sinks down.
- The winds blow away from high pressure.
- A blue H denotes the location of a high pressure system.
- characterised by fine weather with light winds
(c) depression (“low” or “cyclone”);
In the Southern Hemisphere, a depression is a clockwise circulation of winds around a central region of low atmospheric pressure.
- It has lower pressure at its center than the areas around it.
- Air rises up.
- winds blow toward the low pressure.
- a red L denotes the location of a Low pressure system.
- characterised by poor weather and strong winds
(d) ridge of high pressure;
- A ridge is an extension of a high.
- similar conditions to a high
(e) trough of low pressure;
- A trough is an extension of a low.
- similar conditions to a low