November 25, 2024

La Niña Returns for a Second Winter – El Niño’s Cooler Sister

December 1, 2021
This coupling of the atmosphere and ocean changes climatic circulation and jet streams in manner ins which magnify rains in some regions and bring dry spell to others.
For the second year in a row, the cooler sibling to El Niño revealed up at the winter season celebration in the Eastern Pacific. La Niña is expected to stay till at least spring 2022 in the Northern Hemisphere.
Part of the El Niño-Southern Oscillation cycle, La Niña appears when stimulated easterly trade winds magnify the upwelling of cooler water from the depths of the eastern tropical Pacific, triggering a large-scale cooling of the main and eastern Pacific ocean surface near the Equator. This La Niña coupling of the atmosphere and ocean modifies global atmospheric flow and can trigger shifts in the course of mid-latitude jet streams in methods that magnify rains in some areas and bring drought to others.

Part of the El Niño-Southern Oscillation cycle, La Niña appears when energized easterly trade winds magnify the upwelling of cooler water from the depths of the eastern tropical Pacific, causing a large-scale cooling of the central and eastern Pacific ocean surface area near the Equator. In the western Pacific, rainfall can increase significantly over Indonesia and Australia during La Niña. The image above shows conditions across the main and eastern Pacific Ocean as observed from November 26 to December 5, 2021, by the Sentinel-6 Michael Freilich satellite and evaluated by scientists at NASAs Jet Propulsion Laboratory (JPL). The La Niñan occasion that began in late 2020 fits into a larger climate pattern that has actually been going on for almost two years– a cool (unfavorable) phase of the Pacific Decadal Oscillation (PDO). “The brand-new satellite is giving us an excellent picture of this La Niña,” Willis said.

In the western Pacific, rains can increase drastically over Indonesia and Australia during La Niña. Rainfall and clouds end up being more erratic over the eastern and central Pacific Ocean, which can cause dry conditions in Brazil, Argentina, and other parts of South America and wetter conditions over Central America. In North America, cooler and stormier conditions typically embeded in across the Pacific Northwest, while weather condition normally ends up being warmer and drier across the southern United States and northern Mexico. (These and other patterns are shown in the map lower in this story.).
The image above programs conditions throughout the central and eastern Pacific Ocean as observed from November 26 to December 5, 2021, by the Sentinel-6 Michael Freilich satellite and evaluated by researchers at NASAs Jet Propulsion Laboratory (JPL). Tones of blue suggest sea levels that were lower than average; normal sea-level conditions appear white; and reds suggest locations where the ocean stood higher than normal.
” This moderate strength La Niña can be seen in the Sentinel-6 information as a location of lower-than-normal sea level along and listed below the Equator in the eastern and central Pacific,” stated Josh Willis, a climate researcher and oceanographer at JPL. He noted that the deep trough (blue) above the Equator is not the La Niña water mass; it is a shift in the North Equatorial Counter Current, which tends to reinforce throughout La Niñan events.
December 1, 2021.
” This La Niña most likely indicates problem for the American Southwest, which should see lower than regular rainfall this winter,” Willis stated. “This La Niña may not be a whopper, however its still an unwanted indication for an area currently deep into a dry spell.”.
The La Niñan occasion that started in late 2020 fits into a larger environment pattern that has actually been going on for almost 2 years– a cool (unfavorable) stage of the Pacific Decadal Oscillation (PDO). During most of the 1980s and 1990s, the Pacific was locked in a PDO warm stage, which coincided with several strong El Niño events.
In a report launched on December 9, 2021, the NOAA Climate Prediction Center noted that sea surface area temperatures in November in the eastern tropical Pacific ranged from 0.7 to 1.2 degrees Celsius listed below the long-term average and 0.9 ° C below average in the Niño 3.4 region of the tropical Pacific (from 170 ° to 120 ° West longitude). Forecasters predicted La Niña conditions would continue through Northern Hemisphere winter season, with a 60 percent opportunity that the ocean would shift back to neutral conditions during the April through June period.
This La Niña is the first to be observed by Sentinel-6 Michael Freilich, which was introduced in November 2020. “The brand-new satellite is giving us an excellent photo of this La Niña,” Willis stated. “With the public release of the missions climate-quality data, we are now in a position where Sentinel-6 Michael Freilich can soon take control of the environment record of sea level rise, which goes all the way back to the early 1990s.”.
Engineers and researchers have actually spent the previous year adjusting and examining data from the brand-new satellite versus the existing Jason-3 mission. The team is guaranteeing that the new, advanced data associate appropriately with long-lasting records. New, high-resolution Sentinel-6 Michael Freilich information sets were released at the end of November 2020.
NASA Earth Observatory images by Joshua Stevens, utilizing modified Copernicus Sentinel information (2021) processed by the European Space Agency thanks to Josh Willis/NASA/JPL-Caltech, and information adjusted from the Famine Early Warning Systems Network.