What’s raging these days apart from the pandemic? It’s a cyclone. Surely you have heard about raging cyclones all over the world. Within 2 week, 2 different parts of India experienced cyclones. Mumbai and Kolkata were devastated in the month of May and even after a month the situation has not improved much. Meanwhile countries like Mexico have also faced cyclones making people’s life miserable.
Now cyclones are quite common in the tropics and the subtropics. 2020 started with rising temperatures in the pacific belt which resulted in cyclonic formations. There are more than 46 cyclones that have emerged in the region but only a few were deadly. Of this the Cyclone Harold in the South Pacific was the most destructive. But what makes some of these cyclones work while others don’t? Let’s investigate.
How do air circulate?
Now, before we delve deeper into cyclone structure, let us look at how cyclones are formed.
Why and How a Cyclone emerges? It’s a simple process of atmospheric air circulations that causes this.
As the sun rays hit the earth, everything heats up including the air in the sky and the water in the ocean. This heat moves in a systematic way. It moves in layers and passes down from one layer to another. As one layer becomes warm it moves up just like a hot air balloon and the cold air comes down to the surface. This way air is circulated from the equator to the polar region.
Now, if you think the earth as a stationary object this is quite simple. Sun rays fall on the equator. Warm air rises from the equator and then moves through the region to cool down, ultimately descending into the poles as cold air. So, the region where this cold air lands has high atmospheric pressure while the warm equator region has low atmospheric pressure.
But the earth moves like a spinning top, only at a lesser speed as it is quite bigger in size. So everything around it including the atmospheric air and the ocean currents. This turbulence complicates the simple mode of heat movement, called convection. This ultimately results in ocean current and atmospheric currents imbalance. All this makes way for cyclones, hurricanes and tornadoes.
Now, let us look at how these natural elements develop.
As we see the earth rotates in its own axis like slow motion spinning top and hence everything on it bulges and moves along with it.
But this movement of the oceans and air isn’t haphazard. It moves in a systematic pattern. If you put a dot at both the upper and lower end of a spinning top and spin it, you would see that the 2 dots seem to move in different directions. This is exactly what happens on earth.
The ocean currents and the air on the northern part of earth moves in the right hand direction and those at the southern part moves in the left hand direction. The middle equator portion moves in a static kind of way. This is what is known as the Coriolis Effect and this acts as a catalyst for cyclone formation.
How does the Coriolis Effect create cyclones?
Now, the question is how does it create cyclones and why is it crucial in understanding cyclone forming patterns.
So, warm air rises up and creates low pressure in the area. Now, just like water flows from a high level to a lower level unless both are equal. Air too will move from the high pressure zone to the low pressure zone. But the Coriolis effect doesn’t let it do it. It diverts to the right hand side in the northern hemisphere which makes it move in a counterclockwise direction which results in a cyclone.
The opposite happens in the southern hemisphere and the air moves in a clockwise direction. This pattern of circular movements create cyclones
Now, Cold air tries to fall on the surface. It tries to descend in a spiral manner but the Coriolis effect diverts it to the right in the northern hemisphere and to the left in the southern hemisphere. This circular movements in high pressure region creates anticyclones
So, we get circular winds in both the hemispheres depending on the low pressure and high pressure zones. High pressure zones get anti-cyclonic winds and low pressure one get cyclonic winds.
What causes cyclones to be effective?
Now we see these cyclonic and anticyclonic winds developing daily but not all succeed in making proper cyclones. Cyclones emerge when these winds move in counter clockwise inward motion in the low pressure region . As they move inside they suck up clouds and thunderstorms creating a great depression and oncoming cyclone. This is the reason why most cyclones occur around the tropical region because of their warming nature and the spinning movement of the earth.
Now, as the cyclone moves towards land it loses some of its speed and inward movement intensity. Thus releasing some hot air and the thunderstorms.
It is this clouds and thunderstorms gathering which are picked up by satellites and warn us about a cyclone
So, that’s how a cyclone develops and the coriolis effect has a crucial role to play in it. So, the next time you are facing a cyclone you know where it comes from.