Although the Atlantic Niña is much weaker than the Pacific Niña, it can partially counteract La Niña by weakening the summer winds that drive upwelling currents that cool the eastern Pacific.
Why are both happening now?
In July and August 2024, meteorologists Cooling is in the spotlight This is believed to be the result of the Atlantic Niña phenomenon developing along the equator. Surface winds have been weak throughout much of the summer, and sea surface temperatures have been rising. It’s pretty warm until early June.So the signs of an emerging Atlantic Niña phenomenon came as a surprise.
At the same time, the waters along the equator in the eastern Pacific Ocean also cooled. La Niña phenomenon predicted We expect to arrive there by October or November.
Getting the combination of Pacific and Atlantic Niñas Rare but not impossibleIt’s like finding two different, weakly coupled pendulums swinging in opposite directions but moving together over time: La Niña and Atlantic Niño, or the more common combination of El Niño and Atlantic Niña.
Good news or bad news for hurricane season?
An Atlantic Niña may initially be good news for people living in hurricane-prone regions.
Colder than average waters off the coast of Africa Suppressing the occurrence of African easterly waves. these are Concentrations of thunderstorm activity It may become a tropical disturbance and eventually become a tropical storm or hurricane.
Tropical cyclone Extracting energy from the process of evaporating water This is linked to rising sea surface temperatures, so a cooling of the tropical Atlantic could weaken this process, which would provide less energy to thunderstorms and reduce the likelihood of tropical cyclones forming.
However, NOAA Updated Atlantic hurricane season outlookwas released in early August, and the 2024 season is also expected to be very active. Tropical cyclone season is usually From early to mid-September.
There are two reasons behind busy forecasting. Near record-breaking warmth Warmer sea surfaces across much of the North Atlantic could strengthen hurricanes, while the expected development of La Niña in the Pacific would tend to weaken them. Wind shear— Changes in wind speed with altitude destroy hurricanes. The much stronger effects of La Niña may surpass those associated with Atlantic Niña.
Making the problem worse: Global warming
In the past two years Abnormally high sea temperatures Around the Atlantic Ocean and much of the world’s oceans, the two Niña events may provide some relief from cooling in certain regions, but the effect may not last long.
In addition to these cycles, the trend towards global warming caused by increasing greenhouse gas emissions is increasing baseline temperatures, Causes a major hurricane.
