To what extent is the climate of the British Isles a product of the air masses that affect it (40 marks)
To what extent is the climate of the British Isles a product of the air masses that affect it? (40 marks)
The British Isles are a group of islands located off the north-western coast of continental Europe. The climate is usually considered to be temperate maritime; however, the weather is very changeable from place to place and from time to time. Air masses greatly affect the weather experienced in the British Isles and therefore, its climate. An air mass is a body of air with uniform levels of temperature, humidity and pressure acquired from prolonged contact in its source region. Despite having an effect on British climate, there are other factors which play major roles and need to be considered.
Much of the weather that the British Isles are subjected to is brought along by one of the five major air masses which affect the islands from five main source areas. The air masses can be split into two categories: maritime and continental. The three maritime air masses – tropical, polar and arctic – and their influences tend to dominate British weather. The most frequent of all the air masses affecting the Isles is the Polar Maritime (PM) air mass, which is thought to account for 25% of weather experienced in the UK. The air starts off very cold and dry in its source area of Northern Canada and Greenland, but as it tracks west across the relatively warm waters of the North Atlantic Ocean, it warms from below and picks up moisture, becoming unstable. These wet, unstable characteristics bring cumulus clouds and showers throughout the year, particularly along the west coast of Britain, where the air mass first hits. The cooling effect of the sea brings below average temperatures of just 16⁰C in the summer, and conversely, the warming effect brings highs of around 8⁰C in the winter. The arctic maritime air mass is very similar to the PM; however, due to its shorter track over the sea, it brings much colder conditions, often responsible for winter snowfall, especially in
The British Isles are a group of islands located off the north-western coast of continental Europe. The climate is usually considered to be temperate maritime; however, the weather is very changeable from place to place and from time to time. Air masses greatly affect the weather experienced in the British Isles and therefore, its climate. An air mass is a body of air with uniform levels of temperature, humidity and pressure acquired from prolonged contact in its source region. Despite having an effect on British climate, there are other factors which play major roles and need to be considered.
Much of the weather that the British Isles are subjected to is brought along by one of the five major air masses which affect the islands from five main source areas. The air masses can be split into two categories: maritime and continental. The three maritime air masses – tropical, polar and arctic – and their influences tend to dominate British weather. The most frequent of all the air masses affecting the Isles is the Polar Maritime (PM) air mass, which is thought to account for 25% of weather experienced in the UK. The air starts off very cold and dry in its source area of Northern Canada and Greenland, but as it tracks west across the relatively warm waters of the North Atlantic Ocean, it warms from below and picks up moisture, becoming unstable. These wet, unstable characteristics bring cumulus clouds and showers throughout the year, particularly along the west coast of Britain, where the air mass first hits. The cooling effect of the sea brings below average temperatures of just 16⁰C in the summer, and conversely, the warming effect brings highs of around 8⁰C in the winter. The arctic maritime air mass is very similar to the PM; however, due to its shorter track over the sea, it brings much colder conditions, often responsible for winter snowfall, especially in