El Nino is understood as a warming of thesurface water of the eastern and central Pacific Ocean, causingunusual global weather patterns.
El Ninos, as a rule, used to happen every 2-7 years, yet within the last 10 years it has occurred more frequently.
Since first being studied by scientific researchers in the 1950s, thephenomenon has been reported to occur 17 times while La Ninas—theopposite occurrence, where water surface temperatures become unusuallycold, following in the wake of an El Nino--have taken place 13 times.
At present, there are signs that another El Nino has taken shape anddeveloped, said Dao Thi Thuy, Head of the Climate Forecast Division,the Institute of Meteorology, Hydrology and Environment (IMHEN).
As a result, Vietnam’s climate is getting hotter at a time when theweather usually becomes cooler and rainier as autumn sets in (afterJuly on the Chinese lunar calendar). With the weather remaining hot anddry, this fall’s temperatures are likely to be higher than the averageof previous years, Thuy added.
When El Ninos occurred in previous years, the rainfall in Vietnam felland temperatures increased, causing widespread draught in many placesacross the country. In particular, it prolonged the flood season, andfloods were more unpredictable and complex than usual towards the endof the spell.
El Ninos have recently occurred between August 2002 and February 2002,and again in May 2004 through January 2005. The latest appearance wasfrom July-December 2006./.