Unusual symptoms sweeping over nature and environment have become talking points of the environmentalists around the world. The nature now is characterized by inconsistencies and irregularities unknown to us until recently. Variations in weather, nature and frequencies of cyclone, extent of drought and excessive rainfall, global warming and topographical changes etc. have thrown the scientists and administrators into uncertainties about managing the nature and environment in the traditional way. While trying to fathom the underlying reasons of climate change, the scientists have put a new focus on the natural phenomena called El Niño and La Niña. Literal translation of the term El Niño in Spanish is "The male Child". La Niña, chosen as the opposite of El Niño, literally means "The female Child". El Niño, warmer than average waters in the Eastern equatorial Pacific, affects weather around the world.
The fishermen of two south American states Peru and Ecuador have given such names to ocean waters of opposite nature and situation occurring thereof. Under normal circumstances, cold currents flow to the coasts of Peru and Ecuador from the Pacific Ocean when swarms of fish flow in to the fishermen's delight. All of a sudden hot waters appear after a couple of years and the fishes disappear to unknown distances to great frustration of the fishermen. This situation is called El Niño. The hot currents affect fishing and accentuate inclement weather. Crops are damaged. Once the situation subsides, an entirely reverse situation takes the stage. Hot current is followed by cold current. Fishes are aplenty, but it leaves an adverse effect on the weather. The air is dry and there is no rain resulting in drought. The fishermen call it La Niña.
El Niño is the warm phase of the El Niño Southern Oscillation (commonly called ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific including off the Pacific coast of South America. El Niño Southern Oscillation refers to the cycle of warm and cold temperatures, as measured by sea surface temperature, SST, of the tropical central and eastern Pacific Ocean. El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific. The cool phase of ENSO is called "La Niña" with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific. The ENSO cycle, both El Niño and La Niña, causes changes in global temperatures and rainfall.
El Niño and La Niña are opposite phases of what is known as the El Niño-Southern Oscillation (ENSO) cycle. The ENSO cycle is a scientific term that describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific.
La Niña is sometimes referred to as the cold phase of ENSO and El Niño as the warm phase of ENSO. These deviations from normal surface temperatures can have large-scale impacts not only on ocean processes, but also on global weather and climate.
El Niño and La Niña episodes typically last nine to 12 months, but some prolonged events may last for years. While their frequency can be quite irregular, El Niño and La Niña events occur on average every two to seven years. Typically, El Niño occurs more frequently than La Niña.
El Niño was originally recognized by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean. The name was chosen based on the time of year (around December) during which these warm waters events tended to occur.
The term El Niño refers to the large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific.
Typical El Niño effects are likely to develop over North America during the upcoming winter season. Those include warmer-than-average temperatures over western and central Canada, and over the western and northern United States. Wetter-than-average conditions are likely over portions of the U.S. Gulf Coast and Florida, while drier-than-average conditions can be expected in the Ohio Valley and the Pacific Northwest. The presence of El Niño can significantly influence weather patterns, ocean conditions, and marine fisheries across large portions of the globe for an extended period of time.
La Niña is also sometimes called El Viejo, anti-El Niño, or simply "a cold event."
La Niña episodes represent periods of below-average sea surface temperatures across the east-central Equatorial Pacific. Global climate La Niña impacts tend to be opposite those of El Niño impacts. In the tropics, ocean temperature variations in La Niña also tend to be opposite those of El Niño. During a La Niña year, winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest.
There was acute drought in south east Asia in the last part of the twentieth century. Rice, wheat and maize production in Thailand, the Philippines, Indonesia and Bangladesh were affected along side drought. Wild fire burnt 1.5 million acres of forest land in Indonesia. Crops were damaged by drought in Ecuador, Argentina and Chile. The scientists believe, all these happened due to El Niño. Furthermore, La Niña appeared immediately afterwards and excessive rains almost perished Chile and Peru and the scientists predicted that storms will engulf the Atlantic region and south east Asia shall be devoured by excessive rainfall and flood.
This situation arises due to mainly to change in specific atmospheric pressure in Darwin, Australia and Tahiti regions. Normally temperature is higher in equatorial regions. El Niño generally appears every four and a half years and lasts for two years or a little longer. It interrupts the natural air flow, ocean waters and weather and is associated with climatic disruptions. El Nino and La Nina can cause changes in world climate. South Africa experienced a dreadful drought in the nineties of the last century when crops were badly affected and there was famine.
Drought, excessive rainfall, flood and cyclones are now annual events. But whether these are related to El Nino and La Nina is not yet known due to lack of technical research and necessary information. Droughts in this country are created by El Nino and La Nina causes massive floods. According to scientists the unprecedented famine of 1950s was caused by the effects of El Nino. The main cause behind the devastating floods of 1954, 1972-74, 1977-78, 1998 and 2006-07 was La Nina. The heat wave that swept our country last year disrupted normal life. The situation is quite similar this year as well. Temperature is rising and several people died of heat stroke. The situation in India is even worse and there has been heat wave and acute water shortage in the states of Bihar and Rajasthan. About 1500 people have already died of heat stroke so far. In short, regardless of the reasons behind, the ferocity of environmental hazards is intensifying. It is therefore essential that timely forecast particularly against El Nino and La Nina be made so that people can take necessary precautions and preparedness before calamities like wild fire, droughts or floods can cast their gloom on us.
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