Solar energy explains fast yearly retreat of Antarctica's sea ice

In the Southern Hemisphere, the ice cover aroundAntarctica gradually expands from March to October each year. The total ice area increases by 6 times. The sea ice retreats at a faster pace around December when the sun is shining.

The University of Washington led a new research that explains why the ice retreats so quickly.

The study was published in Nature Geoscience.

In spite of the puzzling longer-term trends and the large year-to-year variations in Antarctic sea ice, the seasonal cycle is really consistent, always showing this fast retreat relative to slow growth, said lead author Lettie Roach, who conducted the study.

There were previous studies that looked at whether wind patterns or warm ocean waters were to blame for the asymmetrical sea ice cycle. The study shows that a hot summer day in the middle of the day is like a hot summer day in the late afternoon, with melting sea ice and slower temperature changes.

The researchers found that global climate models reproduced the retreat of sea ice. They built a simple model to show that the reason is the seasonal pattern of incoming solar radiation.

Global warming has caused the ice cover at the North Pole to decrease. Over the last few decades, the ice cover has seensawed. Sea ice around the South Pole is still being studied by researchers.

Roach said that previous studies assumed that the rapid seasonal retreat of the sea ice in the southern part of the world was also unexpected. In terms of the seasonal cycle, the sea ice in the South is behaving as we should expect, and the sea ice in the North is more mysterious.

The researchers are trying to figure out why the sea ice in the north doesn't follow the pattern of retreats and growth. Roach said that the geography of the polar continent may be more straightforward than the sea ice.

The Southern Ocean is an important part of Earth's climate. Cecilia Bitz, a professor of atmospheric sciences at the University of Washington, said that being able to explain the key feature of the sea ice that standard textbooks have had wrong, and showing that the models are reproducing it correctly, is a step toward understanding the system and predicting future changes.

The other co-authors are; Edward Wrigglesworth, a research assistant professor in atmospheric sciences at the University of Wisconsin-Madison, Ian Eisenman, a research scientist at the Scripps Institution of Oceanography, and Till Wagner, a research scientist at the University of Wisconsin-Madison.

More information: Asymmetry in the seasonal cycle of Antarctic sea ice driven by insolation, Nature Geoscience (2022). DOI: 10.1038/s41561-022-00913-6 Journal information: Nature Geoscience Citation: Solar energy explains fast yearly retreat of Antarctica's sea ice (2022, March 28) retrieved 28 March 2022 from https://phys.org/news/2022-03-solar-energy-fast-yearly-retreat.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.