The El Ni?o phenomenon refers to the phenomenon in which the water temperature of the Peruvian Current in the cold waters of the eastern equatorial Pacific increases abnormally and causes mass death of fish. Since this phenomenon usually occurs around Christmas (the birthday of the Son of Jesus), El Nino (El Nino) means the Son in Spanish, hence the name. When this phenomenon occurs in a few years, the water temperature in a large area can be 3°C to 6°C higher than normal. The most severe El Ni?o phenomenon at the end of the 20th century occurred in December 1997. The rise in seawater temperature is often accompanied by the abnormal southward shift of the equatorial convergence zone on the west coast of South America, causing frequent heavy rains in central and northern Peru and the west coast of Ecuador, which are originally relatively arid under the influence of cold currents, causing floods and debris flow disasters. The occurrence of El Ni?o often causes the interannual variability of seawater temperature in low latitudes to peak. Therefore, it has a significant impact not only on low-latitude atmospheric circulation, but even on short-term vibrations of global climate. Over the past 100 years, the famous El Ni?o years are: 1891, 1898, 1925, 1939-1941, 1953, 1957-1958, 1965-1966, 1972-1976, 1982 ~1983 and 1997~1998.
“La Ni?a” means “Daughter of God” in Spanish. It is an overkill after an El Ni?o year. This hydrological characteristic will cause the water temperature in the eastern Pacific to drop and drought to occur. On the contrary, the water temperature in the west will rise and the precipitation will be significantly higher than in normal years. Scientists believe that the hydrological phenomenon of "La Ni?a" will not have a major impact on the world's climate, but it will bring more rainfall that will last for a certain period of time to Guangdong, Fujian, Zhejiang and even the entire southeastern coast.