Beginners Guides:
Climate

What exactly is climate?

Climate is the average weather conditions for a particular region. It is calculated by examining weather over at least thirty years.

What affects climate?

We get different climates because of latitude, distance from the sea, prevailing winds, ocean currents, and altitudes. In turn, climate affects a number of other things, including soil type and quality, and also vegetation.

So why do we get tropical rainforests near the Equator?

Rainforests are hot, and receive lots of rain. This is because there is a build-up of heat on the Equator. Air is forced to rise, causing low pressure. The rising air then cools, causing daily thunderstorms. Hot and dry conditions are perfect for growing plants.

Why aren't deserts on the Equator? That's where the earth receives most sun, isn't it?

This is because the upper air spreads out from the Equator. It cools, becoming denser, and descends back to earth forming a high-pressure area, near to the tropics. As the descending air gets warmer and drier, hot deserts form. So, most of the world's major deserts are between the Tropics, but not on the Equator.

Why do deserts form on the West Side of continents?

This is because the prevailing winds, in the tropic area, come from the East, by the time the winds have reached the west they have lost all their moisture, as precipitation. Also, many deserts have a mountain range to the east. The increase in altitude condenses the air and so even more rain falls before it can reach the desert.

So where does Britain's climate fit into all this?

Because Britain is an island, the Atlantic Ocean to the west, the English Channel to the south, and the North Sea to the east (ha, ha) act as one great big blanket in winter and as an fridge in summer. We have mild winters, but our summers are cooler than those on continental Europe.

Why is this?

Ok, here we go. As the sea is translucent (light can pass through it, but the reflection of an object is distorted through it), the infra-red rays from the sun can heat up a greater volume of this, than land, which is simply a solid mass (the sea can be heated to a greater depth). Thus, in summer, the land (receiving the same amount of heat) becomes far warmer than the sea. Since Britain's prevailing winds come off the sea, they serve to cool coastal regions in summer, whilst inland the temperatures are higher. In winter this affect is reversed as the sea cools far slower than the land.

Does this effect occur all over the world?

Simply, yes. One extreme example is central Siberia. Because it is so far away from the sea, temperatures in summer peak at around 35'C but fall to -50'c in the Winter! Additionally, it hardly ever snows in the winter as there is very little water vapour in the air.

So does anywhere else in the world have a climate like Britain's?

Well, there are several regions of the world which lie on the same latitude as Britain. In the North, there is Canada, Northern Europe, Russia and Japan. In the south, there is southern South America and New Zealand. However, in these places, the other factors are different, whether it be altitude, distance from the sea and so on. At a glance, it looks like Newfoundland in Canada should have similar conditions, but it must be remembered that the air reaching Britain is far wetter than that reaching Newfoundland.

If you find yourself caught in the 'Great British Weather', you may consider buying a pair of Joules wellies. These fantastically designed wellies for ladies and kids feature fantastic patterns which are updated twice a year.

 

 

. 1999-2003 Justin Taylor / John Dray

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