In the summer of 1998, overwhelming heavy rains shrouded the Yangtze River Basin in China, causing the Yangtze River to experience its largest floods since 1954. The rolling turbid current poured out thousands of miles, instantly tearing a 60-meter-wide gap in the Jiujiang City flood control embankment! Coupled with the floods in the Songhua River and Nenjiang River in Northeast China, a total of 29 provinces, autonomous regions, and municipalities directly under the Central Government in China have suffered unprovoked disasters, with more than 100 million people affected and economic losses of more than 160 billion yuan. The reason is that this flood is closely related to the strongest El Niño phenomenon in a century that occurred in 1997.
The El Niño event has raised the water temperature along the coast of Ecuador, causing the death of large numbers of cold-water fish living there. In normal years, the tropical western Pacific is covered by "East Rin" water with high temperatures (more than 29℃ in the center), while the eastern Pacific is occupied by "cold water" with lower temperatures (20 - 26℃). But this pattern is disrupted every 2 to 7 years: the water temperature in the 100 to 200-meter water layer below the Western Pacific Warm Pool begins to rise. This continuously rising body of water flows towards the equatorial eastern Pacific Ocean, which will cause the sea surface temperature in the eastern Pacific to rise. At the same time, the cold water (upwelling) rising there will begin to decrease or even stop, further accelerating the rate of sea water temperature rise. Warm water, 1 - 3 ° C higher than normal years, encroaches southward along the coast of Ecuador, causing the water temperature there to rise rapidly, causing the death of a large number of fish fish living there that prefer cold water, and seabirds that feed on fish for a living due to lack of food. They left one after another, and the fishery suddenly lost vitality, and coastal countries suffered huge losses. Since the worst of this phenomenon often occurs around Christmas, helpless fishermen call it El Niño, the son of God! This abnormal climate phenomenon is also known as the El Niño phenomenon.
Global El Niño events occur approximately every 2 to 7 years and last for 1 to 2 years each time. Since the eastward movement of subsurface water in the Western Pacific Warm Pool is the cause of the El Niño event, some people say that the El Niño event in the eastern Pacific has its roots in the distant Western Pacific.