When air remains in one area for a period of time, it assumes the characteristics of the surface over which it has been present, known as a source region. The temperature of an air mass is determined by its source region (for example, arctic, tropical) whilst its moisture content is dependent on if it has formed over land or sea. Every air mass depends on:
- The source region.
- Travel over land or sea.
- The season.
- The atmospheric characteristics.
Five major air masses affect the UK, and which is more dominant at a particular time is closely related to seasons.
When two air masses meet, a front is formed due to the differences in temperature and density. The Polar front is the most common type.
Are high-pressure areas of descending or stable air. They originate in the upper atmosphere where conditions are dry. Winds are gentle…