Tag Archives: coriolis effect


El-Nino and its effects


El-Nino that creates weather surprises is a meteorological phenomenon that happens every two to seven years in the equatorial pacific region. It represents the abnormal warming of sea temperature.

El-Nino means “Little Boy”  or ‘Christ Child” in Spanish. It disrupts the global weather conditions when the balance between temperature, ocean currents and the wind breaks down, and it brings the two extremes of the climate in action, drought and flood.


The El-Nino activity happens in the pacific region extending from the South America to the North part of Australia, Indonesia and India.

The pacific region is vast and it has Asia & Australia to its west and America located to its east. It receives direct & more sunlight than any other part of the world. Therefore, the weather in the equatorial pacific is warmer.

The El-Nino episodes happens between the months of October and January.


There occurs warm air near the equator. These warm air flows from the equator towards the North Pole.

Due to the rotation of the earth, the Coriolis Effect is created.

This Coriolis Effect causes the warm wind to deflect towards the right (north-east) side of the northern hemisphere. At 30 degree North latitude the warm air cools down and they travel towards the equator from the north-east side to the south-west side of the northern hemisphere.

Simultaneously same kind of wind pattern occurs in the southern hemisphere causing the winds to move from the south-east direction to the north-west of the southern hemisphere.

These winds that travel from the eastern side of both the hemispheres are called as the trade winds or easterly winds.


What makes the difference between a normal year and el-nino year?

In normal year, the trade winds blow across the pacific region from east to west. When they blow they push the warm water from South America towards Indonesia. When the warm water moves away from the eastern pacific, the cold water which is underneath comes to the surface near the South America region. This keeps the central and eastern part of the pacific cooler.

Furthermore, this upwelling water is rich in nutrients and supports the aquatic life than the warm water.

The weather depends upon the temperature of the ocean. If the ocean has warm temperature, then more clouds are formed and there occurs rain fall in that region. Hence, the eastern side of pacific gets rain.

During the El-Nino time, the reverse phenomena happens. The trade winds take the opposite direction, i.e. they flow from west to east. Therefore, the warm water piles up near the South America region. This increases the temperature and brings rainfall to the South America region and it causes the fish to move to the colder regions (deep water) of the ocean.


During El-Nino period the temperature will be abnormal (higher than the normal level). This causes high rainfall on one side of the pacific. On the flip side it brings drier conditions than normal in some areas, sometimes even ending up in drought for an extended period of time.

Pro-longed warmer conditions prevails in the eastern pacific which in turn increases the probability of rainfall. Fishing is affected in the region of Peru, since the fishes tend to stay in the cold regions of the ocean (deep water) where the food is present.

The El-Nino that occurred during the year 1997-98 is the worst ever happened which had caused massive destruction and loss of lives across the globe.

By name, it may take the meaning as “Little Boy” but it has got the power to make the deserts into lakes and vice versa.