Unit 4: Synoptic maps Flashcards
What is a synoptic map?
It is a summary of weather conditions over a particular time
Where is this information gathered?
From weather stations on Marion or Gough islands or airplanee, satellite images, weather balloons, floating weather buoys
How often are the maps updated?
Every 6 hours
How does air move in a high pressure cell?
The air descends (sinks) in an anti-clockwise direction while moving outwards (divergence)
How does air move in a low pressure cell?
The air acsends (rises) in a clockwise direction while moving inwards (convergence)
What is another name for a HP cell?
Anti-cyclone
What is another name for a LP cell?
Cyclone or depression
What are the names of the 3 HP cells that dominate SA?
South Atlantic high pressure cell, South Indian high pressure cell, Kalahari high pressure cell
What is an isobar?
It is a line joining places of equal pressure at sea level
What is air pressure measured in?
Hectopascals (hPa)
What size the isobar interval?
4 hPa
How is a trough formed?
When the isobars bend out around a LP cell
How is a ridge/wedge formed
When the isobars bend out around a HP cell
What is the area between two HP cells known as?
A saddle
What are the symbols for the three types f fronts?
Cold front - a line with triangles
Warm front - a line with semi-circles
Occluded front - blue line with interchanging triangles and semi-circles