Tag: tsunami, floods, cyclones, droughts and landslides

Cyclone and anticyclone are two important types of cyclonic activity. The atmospheric disturbance which involves a closed circulation about a low-pressure center, anticlockwise in the northern hemisphere and clockwise in the southern hemisphere, are called cyclones. On the other hand, anticyclone plays a much less important role in the weather-drama at the surface of the earth in comparison with the cyclone. It denotes on atmospheric system that is just opposite of the cyclonic system.

When the wind is spirally moving in towards a low-pressure center then it is called a cyclone. A cyclone has a low pressure at its center and high pressure on the surrounding sides. The wind movement is anti-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

When the wind blows from the high-pressure center towards the low-pressure center this atmospheric disturbance is known as a cyclone. Cyclone blows anticlockwise in the southern hemisphere. It blows anticlockwise because of the Coriolis force produced by the rotation of the earth.

An area of closed, circular fluid motion rotating in the same direction as the Earth is known as a cyclone. It has a lower pressure inside and higher pressure outside. The center of the cyclone is known as the eye. It has a diameter of 20-50 km. It is the point about which the rest of the storm rotates. It has the lowest atmospheric pressure.

When high speed wind blows from high pressure towards the low pressure centre is known as cyclone. Their frequency, direction and intensity varies from place to place. In terms of direction it blows clock wise in southern hemisphere and anti-cyclone wise in  northern hemisphere. The frequncy and intensity also varies with its location and depending on that cyclones are known in different names in different places.

An anti-cyclone originates when a mass of air with high pressure is encircled by that with low pressure. When such condition occurred the relatively cool and dry wind from high pressure blows out to the surrounding low pressure.  While blows out, the wind turns round and round. In anti-cyclone  there exits high pressure at the center, it is called the center or eye of anti-cyclone.

In the absence of rotation, the wind tends to blow from areas of high pressure to areas of low pressure. The stronger the pressure differences between a high-pressure system and a low-pressure system, the stronger the wind. The coriolis force caused by Earth's rotation gives winds within high-pressure systems their clockwise circulation in the northern hemisphere as the wind moves outward and is deflected right from the center of high pressure and anticlockwise circulation in the southern hemisphere as the wind moves outward and is deflected left from the center of high pressure. Friction with land slows down the wind flowing out of high-pressure systems and causes wind to flow more outward from the center.

Western disturbances, specifically the ones in winter, bring moderate to heavy rain in low-lying areas and heavy snow to mountainous areas of the Indian Subcontinent. They are the cause of most winter and pre-monsoon season rainfall across northwest India.

Natural disasters like cyclones often show early meteorological symptoms or signs, allowing authorities and the public time to make necessary preparations to mitigate damage.

The eye is a region of mostly calm weather at the center of strong tropical cyclones. The eye of a storm is a roughly circular area, typically 30–65 km (20–40 miles) in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the most severe weather occurs.