Geography of senior high school: Why does El Nino occur when Peru's cold current weakens?

El Nino phenomenon refers to the abnormal warming of sea water along the equatorial eastern Pacific Ocean, which usually occurs around Christmas, so it is also called "El Nino".

On the east coast of the Pacific Ocean in Peru, there is a cold current along the coast, which reduces the temperature and humidity and prevails downward flow. On the corresponding west coast of the Pacific Ocean, such as the east coast of Australia, there is a warm current and updraft, which constitutes a large-scale atmospheric circulation. However, when the cold current in Peru weakened, the downward flow weakened and the upward flow increased, which led to the flooding of rainstorm along the coast of Peru. On the east coast of Australia, due to the strengthening of downdraft, a large area of dry and rainless weather has been formed.

Similarly, China is on the west coast of the Pacific Ocean, similar to Australia. After the El Ni? o phenomenon, the updraft in the western Pacific weakened and the downdraft increased, which made it difficult to cause rainfall, resulting in less precipitation, abnormal warming and dry weather in China, especially in the north.