Weather and Climate, Part 2

I finished Part 1 with the Coriolis effect.

I said last time that the warmer air at the equator flows toward the poles. The Coriolis Effect impacts this to cause the major weather patterns.

Since the world is a sphere, the surface of the earth at the equator is moving much faster than the surface at the poles. Like a wheel.
For every revolution the outside of a wheel has to cover a much greater distance in the same time as the centre/hub. So the outside of the wheel is moving at a faster speed. For the Earth this means the air at the Equator is moving faster than the air further north and south.

Given the “westerly” spin of the earth, air moving away from the equator carries this extra speed and generally curves eastwards. So our weather fronts, as you know, come from the Atlantic, not just because it’s a large body of water, but because of the Coriolis Effect. These are our prevailing (or dominant) winds.

Along with this is the different densities of the air dependent on temperature. Warmer air is lighter and rises, while colder denser air slips under the warm air.

By now you’ve realised though that not all weather comes from the west, despite what I’ve said. Depending on your global location the pattern is different.

See the first picture for the global prevailing winds pattern. Of most importance to Ireland are two facts. At 30 deg North Latitude there is a “sub-tropical high” and at 60 Deg. North latitude there is a subpolar low.

When you watch the weather forecast you’ll typical see low pressure systems arrive from the west and flow north-easterly, catching us

And you see some of the winds, particularly equatorial and tropical, go the opposite direction.

Part 3.


One thought on “Weather and Climate, Part 2

  1. Pingback: What Is Cold Water Swimming? Part 1 – What Governs Ocean Temperature? | LoneSwimmer

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