The Coriolis Effect

Though its name might have a foreign sound, the Coriolis effect is familiar to anyone who has watched a spinning ice skater pull his arms inward. In the case of the earth’s rotation, a parcel of air at the equator is farthest from the earth’s pole-to-pole axis, and that means it’s moving the fastest as the planet rotates.

The Coriolis Effect

By the Book

High* and low-pressure areas

are regions of air, sometimes cov­ering an area the sire of several states, where the barometric pressure is higher or lower than the surrounding atmosphere, In general, high pressure produces warmer temperatures, fewer clouds, and better weather. Low – pressure areas are usually cooler, have more clouds, and produce rainy weather.

Подпись: Don't fall into the trap of believing that water in bathtubs and sinks always drains counterclockwise in the Northern Hemisphere. Over such short distances, the Conolis effect has no effect and the currents caused by washing our hands or stepping out of the tub-even the up- and-down movement of hot and cold water-exert a far greater force.

Turbulence

When a parcel of air at the equator is nudged northward, it moves over terrain that is closer to the axis. Like the skater pulling his arms closer to his own rotational axis, the air parcel accelerates, pushing its rotational axis toward the right, or eastward. (The same rule holds true for a parcel of air moving southward toward the equator, except that the south-moving air is slowed like a skater extending his arms. That causes the air to slow, turning it westward to the right.)

The Coriolis effect turns everything to the right, and is partly responsible for causing wind to blow clockwise around a high-pressure area and counterclockwise around a low-pressure area. The rest of the explanation comes from the “pressure gradient force” that causes air to always flow from an area of high pressure toward an area of low pressure.

To start with, air in a high-pressure area begins to move toward a low-pressure area nearby. As soon as it begins moving, the Coriolis effect turns it toward the right, causing the clockwise flow around the high-pressure region.

As the clockwise-moving high-pressure air approaches the low-pressure region, the pressure gradient force begins to balance the Coriolis effect caused by the high – pressure area. Air that moves any closer to the low-pressure region will swirl inward in a counterclockwise direction under the influence of the pressure gradient force, which is stronger close to the low-pressure center than the Coriolis effect.