Download L3 UK Climate

UK Climate
UK Climate is Temperature – Cool, Wet Winters and Warm, Wet Summers
1. Temperature in the UK varies with the seasons. It’s
coldest in winter, it warms up through spring, is
hottest in summer, and then cools down again
through autumn.
2. Temperature ranges from an average of 5°C in
January to 20°C in August.
3. Rainfall in the UK is fairly high all year round, but
it also varies with the seasons. It’s higher in autumn
and winter (an average of 120mm in January) and
lower in spring and summer (an average of 65mm in
May).
4. Winds in the UK are mostly warm south westerlies,
but cold north winds are also common. Wind speed
varies considerably by season – winds are generally
stronger in autumn and winter than in spring and
summer.
UK Climate is a Result of its Latitude and
Location
1) LATITUDE – the UK is at mid-latitude (between 50 and 55°N). It doesn’t get very
hot because the sun is never very high in the sky. It also doesn’t get very cold
because there are several hours of daylight even in winter.
2) LOCATION IN RELATION TO ATMOSPHERIC CELLS – the UK is on the northern
edge of a Ferrel Cell. Surface winds bring warm air from the south, and the warm
air rises. This creates low pressure and causes depressions (low pressure weather
systems), which bring rain throughout the whole year!
3) MARITIME LOCATION – the UK is surrounded by water, which gains and loses heat
more slowly than the land does. This means there are cool winds blowing from the
sea to the land in summer, and warm winds blowing form the sea to the land in
winter. So , the summer is cooler and the winter is warmer than inland locations at
the same latitude.
4) LOCATED NEAR THE GULF STREAM – this makes the UK warmer than places at
the same latitude.
Climates Varies Within the UK
TEMPERATURE – its warmer in
the south because there’s more
isolation (more solar radiation
reaching the ground). This is
because the sun is higher in the
sky and there are more hours of
daylight than in the north. E.g.
annual average maximum
temperature is 13.6°C in
Cornwall, and 9.3°C in the north
of Scotland.
Climates Varies Within the UK
PRECIPITATION – its wetter in the west that
the east, e.g. annual average rainfall is 871mm in
Blackpool (on the west coast), and 565mm in
Cleethorpes (on the east coast). This is because
south westerly surface winds bring warm, wet
air from the Atlantic Ocean. The air reaches the
west side of the UK, and it’s forced upwards over
the land. The air pools, the water vapour
condenses and it rains. This is known as
orographic or relief rainfall. The west of the UK
is generally more mountainous than the east, so
the air masses lose most of their moisture in the
west. The area to the east of the mountains,
where less rain falls, is called the rain shadow.
Climates Varies Within the UK
WIND
1) Winds are stronger in the west, e.g. the
annual average wind speed is 21.7km/h in
St. Mawgan (on the south west coast),
and 16.7km/h in Marham (on the east
coast). This is because south westerly
surface winds come over the ocean –
the ocean is flat so there’s nothing to
slow the winds down. When the winds
hit land, they’re affected by hills and
they become weaker.
2) Winds are stronger at higher altitudes
because there are fewer obstacles to
slow them down.
There are Five Main Air Masses that Affect
the UK
1) Air masses are large volumes of air with a similar temperature and
water vapour content.
2) They cover large areas (several hundred km2) and can travel long
distances.
3) They’re classified by the region they form over:
• Arctic or Polar air masses form at high latitudes (so they’re cooler)
• Tropical air masses form at low latitudes (so they’re warmer)
• Maritime air masses form over oceans ( so they’re got a higher water
vapour content)
• Continental air masses form over land (so they’re got a lower water
vapour content)
4) The UK is affected by five different air masses. Each air mass brings a
different type of weather, which is one of the reasons why the UK’s
weather is so variable.
The are Five Main Air Masses that Affect
the UK
POLAR MARITIME air
masses form over the
North Atlantic Ocean.
They bring cold weather
and rain.
TROPICAL MARITIME air
masses form over the Atlantic
Ocean. They bring warm, wet
air, which causes warm weather
and rain.
TROPICAL
CONTINENTAL air masses
form over Africa. They
bring warm, dry air which
causes hot, dry weather.
ARCTIC MARITIME air
masses form over the Arctic
Ocean. They bring very cold,
wet air which causes cold
weather and rain.
POLAR CONTINENTAL air
masses form over Siberia (in
the Arctic). They bring cold,
dry air which causes very
cold, dry weather. These
air masses can bring snow if
the air picks up moisture
from the North Sea.
Discuss how the climate of the UK is a result of its position on the Earth (8 marks).
Analyse the factors that cause differences in the hazards posed by volcanoes around the world. (40 marks)