Geography Reference
In-Depth Information
Mount Pinatubo in 1991 in the Philippines darkened skies around
the world for over a year. The dust reflected more of the Sun's
energy back into space and therefore the Earth was a little cooler
that year. Unusually cold temperatures caused crop failures and
famine in North America and Europe for two years, following the
eruption of the volcano Tambora in 1815.
REGIONAL CLIMATE AND WEATHER
Climate is a long-term average of daily weather conditions occur-
ring at a location. The decline in the Sun's energy received at the
Earth's surface with latitude is important for determining the climate
of a particular region. However, the distribution of oceans and con-
tinents and the circulation of the oceans and atmosphere are also
important. This means that two locations at the same latitude can
experience very different climates and different types of weather
conditions. Northern Scotland has mild winters while Labrador, at
the same latitude in north east Canada, has very cold winters.
Polar climate and weather
Polar climates consist of two main categories: ice cap and tundra.
Polar ice caps are found in central Greenland and the Antarctic.
They are dominated by high pressure and are extremely cold.
Summer temperatures are generally below 0°C and winter temper-
atures below -40°C. In parts of the Antarctic the average annual
temperature can be close to -50°C and temperatures close to
-90°C have been recorded there. The air is very dry and there is
little precipitation. Most of the polar ice caps can be officially clas-
sified as deserts as they have such little precipitation, typically less
than 100 millimetres per year. This is why many physical geogra-
phers differentiate between hot deserts and cold deserts. The ice
cap environment is made even worse for survival by the strong
winds which occur because the ice caps cool the air around them
causing a sinking of air from the high centre of the ice caps (the
Antarctic interior is 3,500 metres high) to the coast.
Polar tundra climates are found in northern Scandinavia, Siberia,
Iceland, coastal Greenland and high latitudes of North America
(see Figure 5.1 in Chapter 5). The temperature of the warmest
