Recently, the topic "Super strong El Niño has formed" has become a hot topic. The reporter learned from the National Climate Center of the China Meteorological Administration that an "eastern-type super strong El Niño event" was officially formed in September this year. This event developed rapidly and with strong intensity, and is expected to become the strongest El Niño event since systematic monitoring began. Faced with these statements, many people have also raised questions: Why does the rising temperature of the water in the equatorial Pacific affect the weather in distant places? El Niño is coming, will this winter be warmer? Will next summer be hotter? Are heavy rains, typhoons, and droughts also attributed to it?
Why does El Niño make the Pacific Ocean "heat"?
As an area of the Pacific Ocean heats up, the weather around the world will "change" accordingly. Therefore, El Niño has always been considered the "climate remote control" in the Pacific Ocean. So, what does this "super strong El Niño" mean?
You can think of it as a "high fever" in the Pacific Ocean: the sea water in a large area of the equatorial central and eastern Pacific Ocean has heated up abnormally. This "hot water" has stirred up the global atmosphere and caused "chaos" in the weather around the world.
Warm water and trade winds: air-sea linkage during El Niño
Under normal circumstances, the Pacific Ocean is like a basin of swinging bath water: Northeast trade winds and southeast trade winds prevail on the surface of the tropical central and eastern Pacific. Under the influence of the trade winds, warm seawater on the Pacific surface accumulates in the west, causing the sea surface temperature in the western Pacific to rise and active convection. The coast of South America is affected by the upwelling of cold water and forms a downdraft. This zonal circulation in which the western Pacific rises and the eastern Pacific sinks is called the Walker circulation in meteorology.
But when El Niño occurs, it is equivalent to a sudden external force tilting the water basin in the opposite direction. The weakening of trade winds leads to abnormal westerly winds. The warm water in the Western Pacific Warm Pool flows back to the central and eastern Pacific. The cold bath water along the coast of South America becomes abnormally warm, causing the Walker circulation to weaken. This imbalance will trigger a chain reaction.
Southeast Asia, where it should be raining, is suffering from drought, while South America, which should be dry, is suffering from heavy rains. If fish stocks are not adapted to the excessively high sea temperatures in the central and eastern Pacific Ocean, they will die in large numbers, and Peruvian fishermen will have no fish to catch. These fishermen discovered that El Niño would appear every 2 to 7 years, and had the most obvious impact on fishing around Christmas, so they called this phenomenon "El Niño," which means the Holy Child.
From 1972 to 1973, the Peruvian fishery industry suffered a sudden collapse. Severe droughts in some parts of the world led to significant reductions in food production, drying up of rivers, and scarcity of water resources, while in other places there were extremely heavy rains and devastating floods. At that time, meteorologists were alarmed by a series of simultaneous climate anomalies around the world, but they did not know that this turned out to be a strong El Niño event.
El Niño is like the "flu" in the Pacific. Although it originates from the equatorial central and eastern Pacific Ocean, it can stir up wind and rain around the world.
How strong is the strongest El Niño event?
Meteorological experts said that the current round of El Niño events has officially formed in September this year and is expected to become the strongest El Niño event since systematic monitoring. "The strongest in history" is not a random feeling, but has strict criteria for judgment. How strong is the strongest El Niño?
According to meteorological satellite monitoring, since May, the equatorial central and eastern Pacific has entered an El Niño state, and sea temperatures in the key Niño 3.4 zone have continued to rise. From July to September, the moving average of the SST index in the Niño 3.4 zone exceeded 2.5°C, reaching the standard for a super event. The meteorological department predicts that in the next three months, sea surface temperatures in the equatorial central and eastern Pacific will continue to rise, reaching a peak in late autumn and early winter. This El Niño event will become the strongest El Niño event since systematic monitoring.
Zhao Junhu, chief forecaster of the National Climate Center of the China Meteorological Administration: The National Climate Center mainly monitors the sea temperature index in the Niño 3.4 zone in a specific area. When the three-month moving average of the index reaches or exceeds 0.5°C and lasts for at least 5 months, it is determined to be an El Niño event. The intensity of the event is defined as its peak value, which is the maximum value reached by the three-month moving average of the SST index in the Niño 3.4 zone. An event peak reaching or exceeding 0.5°C but less than 1.3°C is defined as a weak event, reaching or exceeding 1.3°C but less than 2.0°C is defined as a medium event, reaching or exceeding 2.0°C is defined as a strong event, and reaching or exceeding 2.5°C is defined as a super strong event.
It is expected that the sea surface temperature in the central and eastern equatorial Pacific will continue to fluctuate and rise, reaching the peak of this event around November and December. The intensity is expected to exceed the three super events in history, namely 1982 to 1983, 1997 to 1998 and 2015 to 2016, becoming the strongest since there are observational records. This event has outstanding characteristics such as rapid development, strong intensity, and significant impact on climate.
Does a super strong El Niño mean super high temperatures? no!
Since El Niño can cause seawater temperatures to rise, will a super strong El Niño mean super high temperatures? Not really.
Super El Niño is like a powerful "global climate amplifier". It will "shuffle" the transport paths of atmospheric energy and moisture, which is equivalent to pressing the "master switch" of global weather. However, this is only a "step-up" for climate anomalies. Super strong El Niño may trigger a series of extreme events in the region or the world - heavy rains in some places, droughts in other places, typhoon paths, high temperature and heat waves will be "rearranged".
Will it be cold or warm this autumn and winter? Why is the “biggest event” next year?
The impact of El Niño focuses on the response to the atmosphere, which can be an immediate response or a delayed effect, related to different stages of its development. So, what impact will this super El Niño event have on our country’s climate? Will extreme climate anomalies occur this autumn and winter or even next spring and summer?
Meteorological experts said that for China, the impact of El Niño is more complicated. Usually in the development years of El Niño, floods are prone to occur in the area south of the Yangtze River in my country; the number of typhoons in the northwest Pacific is relatively large, the location of typhoons is east and south, and the intensity is relatively strong; my country has a higher probability of a "warm winter" in winter, but the fluctuations in cold and warm temperatures are still obvious. In the declining years of El Niño, the risk of flooding in the Yangtze River Basin is higher, and the number of typhoons is relatively low. In summer, temperatures in most parts of my country are relatively high, and high-temperature heat waves may be stronger.
