El Nino

What is El Nino Phenomena?

El Nino is defined such a phenomenon that is associated with the warming of the tropical Pacific. This generally happens in a span of every three to seven years and the lasting duration is around 12 to 18 months.

It is basically a meteorological act where the rise in temperature and fall in atmospheric pressure is noticed. The origination of El Nino takes place in the central and eastern Pacific Oceans and is responsible for disturbing the climate patterns at the global level.

Basics of El Nino

El Nino is a term that describes the disturbance in the atmospheric system of the tropical Pacific. It has a severe impact on the wind that results in changes in the global climate pattern thereby causing floods and droughts at a worldwide level.

It is quite complex in nature and thus prediction of its occurrence is a difficult task.

The El Nino – Southern Oscillation commonly abbreviated as ENSO is such a climate pattern where the temperature change of water is involved. Not only this, the sea level pressure patterns, lower and upper-level winds but also, and the tropical rainfall across the Pacific basin are also modulated by El Nino. Climatologists are trying to find the shifts in air columns, and disruption in currents in the Indian ocean due to Southern Oscillation.

One should note here that sometimes monsoon is affected by El Nino, sometimes it is not.

As we have mentioned recently that climatologists are studying the effects of El Nino and they basically predict two kinds of forecasts. These are as follows:

  • Statistical forecast which is based on previous records, and
  • Dynamic forecast is the result of numerical models of the atmospheric system. One of the numerical models is hydrodynamic equations.
    It is nothing but the mathematical representations of physical laws where motion, heat, and water mass are included. Accordingly, climatologists form models so as to predict how the various atmospheric components like clouds and air currents behave.

Occurrence of El Nino

For the duration of about 2 to 7 years, the water of the tropical Pacific Ocean gets warm or cool in between 1 to 3° C in comparison to normal. The irregularity of a warm or cool pattern is regarded as the ENSO cycle. It affects the rainfall distribution and strongly influences the weather conditions in the US and other parts of the world. Other than El Nino, La-Nina is also an extreme phase of the ENSO cycle.

Earlier effects of El Nino:

  1. It resulted in warmer winters and stronger storms in Canada and Alaska.
  2. It caused more winter rain in some regions of Central US.
  3. Floods and mudslides also occurred in Peru, Ecuador and Bolivia.
  4. Typhoons occurred when sea water in Northwestern Pacific gets warmer.
  5. Droughts in Brazil are the result of El Nino and this has resultantly affected crop production in the northern regions.
  6. Due to El Nino heavy rains were caused in Argentina and Central Africa.
  7. It results in weak monsoon conditions in Southeast Asia thereby causing reduced crop production.
  8. In most of the cases, El Nino caused droughts in India.
  9. Due to warmer weather, the icebergs are drifting towards south in Eastern Canada.

One should note here that according to a Delhi-based International Development Research Centre, if the temperature rises by 1 °C then it may result in rise in the number of malaria cases by 337%. Thus, it is said that El Nino phenomenon leads to cause severe ill health conditions.

Drought and El Nino

We have already discussed that El Nino is described as warming of tropical Pacific basin. Due to El Nino, swings in the atmospheric pressure are noticed between the eastern and western Pacific and this is called Southern Oscillation. Hence collectively the phenomenon is regarded as ENSO.

Drought is known to be the most commonly occurring natural phenomenon. It hampers the food security of the country as it affects the agricultural conditions which show high dependency on the monsoon. As prevention towards drought, researchers have tried to find evidence that can prove links between drought and ENSO.

One should note some points over here that:

  • The occurrence of drought may be frequency but is not cyclic as ENSO.
  • There are irregularities in various cycles of ENSO.
  • If ENSO is occurring then it is not necessary that drought too will occur as droughts might be associated with other oceanic, atmospheric and terrestrial conditions.
  • The occurrence of ENSO, surely corresponds to a condition of limited rainfall.

This is all about El Nino.

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