PRESSURE GRADIENT AND CORIOLIS FORCE

What is the Pressure Gradient Force (PGF)?

The force that causes air to flow from high pressure to low pressure. The greater the pressure difference over a distance, the stronger the wind.

How do closely spaced isobars differ from widely spaced isobars?

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Closely spaced isobars = steep pressure gradient = strong winds. Widely spaced isobars = gentle pressure gradient = weak/light winds

What is the Coriolis Force?

A force caused by the Earth's rotation that deflects moving air from its original straight path. It deflects winds to the RIGHT in the Northern Hemisphere and to the LEFT in the Southern Hemisphere.

What causes the Coriolis Force?

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The Earth rotates from west to east at different speeds — fastest at the equator (1670 km/h) and slowest at the poles (290 km/h). This difference in rotational speed deflects moving air

Where is the Coriolis effect strongest and weakest?

Strongest near the poles (greatest difference in rotational speed). Weakest/zero at the equator.

In what direction do winds rotate around a LOW pressure system in the Southern Hemisphere?

Clockwise (because air deflects to the left as it moves toward the centre of low pressure).

In what direction do winds rotate around a HIGH pressure system in the Southern Hemisphere?

Anticlockwise (air moves outward from high pressure and deflects to the left).