The Coriolis effect is a force that is caused by the rotation of the Earth in the space. The Coriolis effect deviates the trajectory from the objects that are thrown in a straight line in the surface of the Earth, either to the right in the north hemisphere or to the left in the south hemisphere. The Coriolis effect, or also called Coriolis force, acts onto the air and water masses. It is for this reason that tornados and hurricanes form, due to the Coriolis force, which makes to turn the wind in different directions, and, for consequence, it provokes this phenomenons. It is also due to this force that there are no hurricanes in the Equator.
This image that shows us the different tornados and hurricanes that were registered the last years leaves no doubts: along the Equator’s zone there isn’t a reason for which we have to fright from hurricanes.
The Earth turns onto its axis in a speed of 1 600 km/h in the Equator, which supposes a 40 000 kilometres movement after a day. Meanwhile, a person which was situated exactly in one of the poles will not have moved even a kilometre. This difference provokes that the rotation of the planet creates hurricanes in determined latitudes, mainly in which are represented in the image.
As the teacher of meteorology from the University of Hawaii Gary Barnes explains to us, in his institution website, and thanks to his observation of the hurricanes, he indicates that the hurricanes don’t form within less than 5 degrees from the Equator’s line, which are approximately about 300 kilometres. The scientific reason for which hurricanes don’t form in this zone is very simple. In this part of the Earth, the Coriolis force is to weak for the air to rotate around an air bag at small pressure. As consequence, if the air doesn’t turn, there aren’t tropical storms.
However, and even if it is very unusual, the formation of hurricanes near the Equator has been seen, phenomenons that, in theory, hadn’t had to take place. It is the case of the Varmei typhoon (it can be seen in the image beside the African littoral), which was formed only at 150 kilometres from the Equator’s line in 2001, in the south of the Chinese sea.
The investigators from the NASA that studied the case of the Varmei typhoon, discovered that a mixture of meteorological and topographical conditions, which substituted the Earth’s rotation function, and as result it created this typhoon. According to their calculations, the probability that this phenomenon takes place is of one in a period that covers between 100 and 400 years.