The weather phenomenon looks like 98, and our country welcomes La Nina

Original title: El Ni ñ o "retirement" does not "fade"

El Nino and La Nina (Network Picture)

On June 3, some vehicles were flooded at the Liujiang Grand Wharf in Congjiang County, Guizhou Province. (network Picture: Xinhuanet)

As early as the beginning of this year, meteorologists predicted that the super El Ni ñ o event could end by the end of May. At the regular news conference of the China Meteorological Administration held on June 3, the news of El Ni ñ o's "retirement" was finally officially announced.

However, meteorologists warn that although El Ni ñ o "retires", it will not "fade" easily, and its influence will continue throughout the flood season, and the Yangtze River, Songhua River, Huaihe River and Xijiang River basins are still sounding alarm bells.

It can be called "the strongest El Nino in history".

The El Nino event began in September 2014. After more than a year of "baptism", the public is no longer unfamiliar with the El Nino incident. This phenomenon, which occurs in the central and eastern equatorial Pacific Ocean, continues to be abnormally warm on a large scale, and may have a far-reaching impact on the global climate through the interaction of the atmospheric circulation system.

Reviewing the history, there have been 14 El Nino events in the world since 1951, of which 3 have reached the super-strong level, namely, the 1982 / 1983 El Nino event, the 1997 / 1998 El Nino event and this event.

Song Lianchun, director of the National Climate Center, pointed out that in terms of peak intensity, duration, cumulative sea surface temperature anomaly, and months with a continuous anomaly of more than 2.0 degrees Celsius, this event formed a "comprehensive surpassing" of the previous two super-strong El Ninos, which can be called the "strongest" El Nino in history.

For China, because China is a typical monsoon climate country, the biggest feature is the large interannual variability of precipitation, which will be more significant in the abnormal SST state. Under the action of El Ni ñ o, the anticyclonic high pressure circulation system from the Philippines to the South China Sea can be excited. This circulation system is superimposed on the subtropical high, which makes the western Pacific subtropical high stronger and southward, which is not conducive to the movement of the rain belt in the flood season.

In other words, under the influence of El Ni ñ o, the "god of rain" may come to a particular area more exclusively, leading to a rapid increase in the probability of major floods in that area.

Judging from the great flood in the Yangtze River Basin in 1998, it is precisely because the whole rain belt in the flood season continues to surround the Yangtze River, which leads to the situation of "peak-to-peak" flood in the Yangtze River, resulting in a major dangerous situation in the basin.

The whole country may be "waterlogged at both ends and drought in the middle"

Since the beginning of the flood season, there have been more than ten rounds of heavy rainfall in southern China, and the high frequency and intensity are very rare.

According to the statistics of the State General Administration of Flood Control, the precipitation since the beginning of the flood season has been the second largest in the past 55 years, with some areas in Jiangnan, South China, Southwest, Northwest and Northeast doubling. 118 rivers such as Xiangjiang River in Hunan Province, Ganjiang River in Jiangxi Province, Beijiang River in Guangdong Province, Guijiang River in Guangxi and Minjiang River in Fujian Province have experienced super-alarm floods, the most in the same period in the past five years.

The reporter learned from the Central Meteorological Observatory that this year, the South China Sea summer monsoon broke out at the end of May, which means that the southwest water vapor transport is significantly enhanced. The low-level southwest wind will continuously transport the abundant water vapor from the tropical ocean to the East Asian continent, the monsoon rain belt will gradually advance to the central and eastern part of China, and China will enter the main flood season in an all-round way.

The latest forecast of the State General Administration of Prevention and Control shows that there is generally more precipitation in China during the flood season this year, and specifically points out that major floods may occur in the Yangtze River, Songhua River, Huaihe River and Xijiang River, and the possibility of floods in other major rivers cannot be ruled out. At the same time, severe drought may occur in North China and other places. This means that during the flood season this year, there may be a "drought between two heads of waterlogging" throughout the country, that is, the southern and northeastern regions will suffer from floods, while the North China region will be dominated by droughts, which requires both flood control and drought relief, and the situation of flood control and drought relief is grim.

"so far, many climatic phenomena similar to those in 1998 have occurred in the atmosphere. People need to take 1998 as the standard to prepare for major floods and fight an uphill battle against possible floods in the Yangtze River basin." Zhou Bing, chief expert on climate monitoring at the National Climate Center, said.

La Nina "takes over" El Nino

The monitoring of climate experts shows that the cold water in the equatorial Middle East and Pacific Ocean is developing rapidly. If the cooling range and time of sea water reach a certain critical value, it may lead to La Nina, the opposite of El Ni ñ o.

The harm of La Nina is usually weaker than that of El Nino, but the impact of La Nina events in the past 60 years shows that after La Nina occurred, there is more autumn rain in some parts of China, less precipitation and low temperature in most of the country in winter. Although La Nina phenomenon may not have a direct effect on the main flood season, its influence on the climate trend in the later period can not be ignored.

In addition to rainfall, El Ni ñ o also has an important impact on global agricultural production. Based on the analysis of meteorological and satellite remote sensing data and crop yield prediction models, relevant experts from the China Meteorological Administration believe that due to the influence of El Ni ñ o, the meteorological conditions of many countries are deviated this year, and it is expected that the production of Indian wheat and Brazilian corn may be reduced this year, thus driving up the price of international agricultural products.

For our country, it is the summer harvest season. Experts suggest that in the face of the increasingly severe weather situation in the main flood season, all parts of the summer harvest should seize the rainfall gap, harvest and dry in time to ensure that the particles return to the warehouse. (Xinhua News Agency reporter Lin Hui Yu Wenjing)