Why do hurricanes move counterclockwise and others clockwise?

Arabia Weather - Hurricanes and tornadoes apply to weather systems that are characterized by their rotational movement around a specific center. Given the direction of their movement, these weather phenomena can be classified either counterclockwise or clockwise, and here we will provide a simplified explanation of the reason for these contradictory movements.

Coriolis effect

Which is also known as Coriolis deflection, is the effect resulting from the deflection of a body moving on or near the surface due to the rotation of the planet. This effect is of great importance in several fields, including meteorology and oceanography. The Earth's rotation plays a prominent role in determining climate and weather, in addition to its effect on the condition and flow of the oceans through what is known as the Coriolis effect.

Why is the Coriolis effect called this?

Named after the French mathematician Gaspard Gustave de Coriolis (born in 1792), the Coriolis effect refers to the curved path that objects moving on the Earth's surface appear to follow as a result of the planet's rotation.

As the Earth rotates, points near the equator - such as the countries of Ecuador and Kenya - move much more quickly compared to places near the poles, and this is due to the shape of the Earth, which is similar to a regular sphere, where its circumference near the equator is much larger than near its top and bottom. Although all locations on the Earth's surface take one 24-hour day, points closer to the equator have to travel longer distances in the same time, which means they move more quickly. Scientists point out that it has more "angular momentum" , which is why rockets are usually launched from areas close to the equator, such as Cape Canaveral in Florida, USA. These locations give the missiles a high initial speed, enabling them to reach orbit using the least amount of fuel possible.

Why do hurricanes move counterclockwise and others clockwise?

The Coriolis effect affects wind patterns, which in turn determine how ocean currents move. If you imagine that winds near the equator flow north, and those winds start at a certain speed; Because of the Earth's rotation (near the equator, the Earth rotates at about 1,600 kilometers per hour (1,000 mph) from west to east, and when winds move north toward the North Pole, they move over parts of the Earth that rotate progressively more slowly.

Since the winds retain their angular momentum, they continue to move from west to east, bypassing the part of the Earth that is rotating slower below them. As a result, the winds appear to bend toward the east (i.e. to the right). This is the Coriolis effect. As winds flowing southward from The equator will also bend toward the east.

Answer: The Coriolis effect is responsible for many meteorological and oceanographic phenomena. For example, due to the Coriolis effect, hurricanes in the Northern Hemisphere rotate in a counterclockwise direction, while hurricanes in the Southern Hemisphere (known as hurricanes) rotate in a clockwise direction. Hourly, ocean currents known as “eddies” also spin in spiral patterns thanks to the Coriolis effect.

The effect of the Earth's sphericity on the direction of hurricanes

Meteorologist Dr. Khaled Al-Zaaq explained the reason behind hurricanes heading in two opposite directions in different regions, and linked this effect to the sphericity of the Earth. Al-Zaaq pointed out that the term “hurricane” among the ancient Arabs was applied to spiral winds that rotate around themselves in a strong way. It rises to great heights, similar to a column, while meteorologists use the term "cyclone" to refer to the low pressure area that brings winds toward its center.

Al-Zaaq explained that the center of the hurricane is usually calm, while the “ edges” or outer edges are stormy, and as a result of the Earth’s rotation around itself and its sphericity, the movement of the hurricane is counterclockwise in the areas north of the equator, while it is clockwise in the areas located south of the equator. .

He explained that the hurricane goes through different stages before it turns into a full-fledged hurricane. It begins with the stage of low air pressure (clouds) , then if its speed and movement increase, it turns into a tropical storm. If it is located in the areas between the Tropics of Cancer and Capricorn, where the sun is perpendicular to it in summer and winter, if its speed reaches 64 knots, it is classified as a hurricane.

Al-Zaaq explained that a hurricane is classified according to its degrees, where the first degree (simple hurricane) includes a speed ranging between 64 knots and 83 knots, the second degree (medium) has a speed ranging between 84 knots and 95 knots, while the third degree (strong) is considered to be from 96 to 110 knots. Decade The hurricane begins at category four (very strong) when its speed reaches 111 knots, and continues to increase until it reaches category five (destructive category) when its speed exceeds 136 knots.

Also know:

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Are there hurricanes on other planets?

140 years of hurricanes and storms in the Sultanate of Oman

Sources:

education.nationalgeographic

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