Maybe its ice Arctic Disappeared but only recently Antarctica The opposite was happening. However, that trend was broken in February, and the southern hemisphere saw a record low snowfall, the second in five years.
According to information from SatelliteFor the first time since polar observations began in 1978, Antarctic sea ice was below 2 million square kilometers.
In an article published this Tuesday, April 19, 2022, in Advances in the Atmosphere, a team of university researchers Sun Yat-sen And Guangdong South Marine Science and Engineering Laboratory (Zhuhai), In. ChinaThe search for its causes has analyzed this phenomenon, although it remains unclear.
In recent years, global warming has led to a rapid decline in the amount of Arctic sea ice, but so far, at other poles of the world, Antarctic ice has increased by about one percent per decade since the late 1970’s.
This trend was broken in 2017, and sea ice in the Southern Hemisphere hit its historic lowest, which, now, five years later, has been repeated.
On February 25, 2022, at the end of the summer in the Southern Hemisphere, data showed that the Bellingshausen / Amundsen Sea, the Waddell Sea, and the western Indian Ocean were significantly lower than normal ice.
In addition, across the region, sea ice levels were 30% lower than the three-decade reference period of 1981-2010.
In recent years, many factors have been suggested Variability Antarctic ocean ice, but there is still no scientific consensus and the phenomenon remains theoretical and undiscovered.
A new minimum presence of sea ice in such a short time prompted Chinese researchers to study what happened and why.
Explanation of events
After analyzing satellite data, they found that in the summer, thermodynamics dominates the processes that melt sea ice, creating an imbalance in heat transfer at the poles of the Bellingshausen / Amundsen Sea, the western Pacific Ocean, and the East Waddell Sea. Special
Global infrared radiation, light, temperature and albedo (the “white” of the surface. The whiter it is, the higher and darker the reflection of the mentioned radiation, the greater the absorption).
“Sea ice is darker, whiter than turbulent oceans, so there is less heat reflection and more heat absorption, which melts more sea ice and creates a vicious cycle of more heat absorption,” explains Dr. Clihua Young, a researcher and co-author of the study.
In spring, however, both thermodynamics and kinetics contribute to the amount of sea ice.
The authors point out that according to data from the U.S. National Oceanographic and Atmospheric Administration (NOAA), new Antarctic sea ice volume records match two weather events: La Nina and a positive southern annular mode (SAM).
SAM is a belt of strong westerly winds or low pressure that surrounds the continent and moves north or south, while La Nina describes a type of strong winds that force warm water to flow from the surface of the ocean from South America to Indonesia. Tropical
These two events affected the lower reaches of the Amundsen Sea (ASL), the center of low atmospheric pressure at the southern tip of the Pacific Ocean and off the coast of West Antarctica.
Therefore, “if tropical variability has such an effect, it is a place of study,” said Jinfei Wang, co-author of the work.
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