The climate refers to the prevailing average weather patterns of a region over long period of time.
For example over a thirty to fifty year period.
Weather is the daily atmospheric conditions consisting of precipitation
temperature, humidity, wind and sunshine.
Around the world there are different climate zones.
In some regions there are hot and dry deserts.
In other places there are warm and wet tropical rainforests
while other places are covered in ice.
Why is this so?
Now let's examine the main factors that influence the climate of a region.
Latitude refers to location on the globe in relation to the equator.
Generally the closer to the equator a place is located the warmer the temperature is.
While the further away from the equator, the colder the temperature is likely to be.
This is because on the equator sunlight or insolation strikes the Earth at roughly a 90 degree angle.
This results in intense solar energy as there is a consistent length of day.
That is 12 hours a day, 365 days a year.
Regions close to the equator have warm temperatures all year-round.
Tropical rainforests thrive in equatorial regions
since plants love this consistent light that powers photosynthesis.
Because the earth is spherical this solar energy diminishes as you move further north or south of the equator.
Regions closer to the poles have four seasons and very cold winters.
Altitude refers to the height of land above sea level.
Saturated air cools at the rate of 0.6 degrees Celsius per hundred vertical meters,
so at 1,000 meters it will be 6 degrees cooler than at the same latitude at sea level.
Therefore high altitude regions such as the Himalayas will be must cooler than
other locations at sea level on similar latitude such as Shanghai.
Mountains can also influence climate in other ways.
For example they can produce what is known as orographic rainfall.
This occurs when moist air is forced to rise over mountains.
The windward side of the mountain will have a wet climate,
while the sheltered leeward side usually has a drier climate.
We call this a rain shadow area.
For example in New Zealand's South Island, the prevailing westerly winds force moist
air from the Tasman Sea to rise over Southern Alps.
Most of the rainfall is dumped on the west coast which has the wettest climate in New Zealand.
The climate east of the ranges in Canterbury is dry.
Relief features can also cause wind funneling.
Cape Horn for example is infamous for its winds due to the wind funnel between Cape Horn and Chile in the Antarctic peninsula.
Another windy place affected by relief is Wellington, the capital city of New Zealand.
This is due to its location on the Cook Strait, the waterway between the North and South Islands.
This tunnel is having the effect of being an artificial wind funnel. It's blowing like crazy here.
It's the same effect that you get in the Cook Strait where the North and South
Islands are your two land masses and the wind is pushed through the Cook Strait.
The size of a land form and proximity to oceans is another important climatic influence.
Small land masses such as islands have maritime climates.
Islands have small temperature variations due to the moderation of the climate by the sea.
Auckland in New Zealand for example has a relatively low temperature variation,
being located on an isthmus surrounded by water with a harbour either side.
Auckland's average daily maximum temperature is 23.7 degrees Celsius in February
and 14.5 degrees Celsius in July.
That is a range of only 9.3 degrees Celsius.
Even on large land masses coastal islands have moderate temperatures all
year round, as they are moderated by moisture laden sea breezes.
For example, Sydney in Australia.
Large continental land masses such as Asia have extremes of climate.
For example, one town in Russia has the largest temperature range in the world.
That is a temperature range of 61.8 degrees Celsius.
Ocean currents also have a big influence on climate.
70 percent of this planet is ocean.
When an air mass passes over a warm ocean current the air mass is warmed.
When an air mass passes over a cold ocean current it is cooled.
Finally, the world is divided into a series of air pressure systems.
Some are high pressure and some are low pressure.
Air pressure is measured in millibars, with low pressure being associated with high winds, rainfall and warm air.
High pressure is associated with clear skies and a greater temperature range,
since there are no clouds to block incoming solar radiation during the day
and no clouds to stop radiation escaping during the night.
There are high pressure areas at the poles and subtropics,
and low pressure air cells at the tropics and sub-polar regions.