image: Heating in Tasman Sea causes warm winters and melting ice in the antarctic. view more
Credit: Kazutoshi Sato (Kitami Institute of Technology)
The melting of the Earth's ice cover intensified in the 20th century, with glaciers and sea ice in the Arctic and Antarctic regions melting at alarming speeds. In fact, The Antarctic Peninsula (AP), which is the only landmass of Antarctica extending out past the Antarctic Circle, was found to be one of the most rapidly warming regions on the planet during the second half of the 20th century. This rapid change in climate has raised serious concerns of rising sea levels the world over.
Multiple factors have been associated with the melting of the ice cover: the primary factor being the greenhouse gas emissions from human activities that cause warming up of the atmosphere and the oceans and the consequent ice melting. Apart from this, atmospheric variations, ocean currents, and wind patterns also play a significant role. Now, a collaborative group of scientists from Japan and Australia--led by Assistant Professor Kazutoshi Sato from Kitami Institute of Technology and Associate Professor Jun Inoue from National Institute of Polar Research in Japan--has focused efforts on understanding how fluctuations in these climatic factors affect the warming of the Antarctic. They have documented their findings in a brand-new article published in Nature Communications.
Previous studies have examined the relationship between the wind dynamics over the Southern Ocean (also called SO; located north of Antarctica) and climate variability in tropical oceans. It was found that heating in tropical regions generates atmospheric waves called "Rossby wave trains" from the tropics to the Antarctic region via the SO, which causes heating of the West Antarctic region. Interestingly, Rossby waves are an attempt of nature to balance heat in the atmosphere as they transfer heat from the tropics to the poles and cold air towards the tropics.
On the path of understanding the warming of AP, Dr. Sato points out, "The impacts of climate variabilities over the mid-latitudes of the Southern Hemisphere on this Antarctic warming have yet to be quantified". His team addressed this gap by looking at the climate changes in the Tasman Sea located between Australia and New Zealand and the SO and drew correlations with temperature variations in the AP.
Dr. Sato and his team analyzed the temperature data from six stations in AP and the wind and cyclone patterns over the Tasman sea and the SO from 1979 to 2019. They found that even without unusual heating in the tropics, only the heating in the Tasman Sea modifies the wind patterns over the SO and forces the Rossby waves to move even deeper into the Amundsen sea low, a low-pressure area lying to the west of the AP. This larger pressure gradient causes stronger colder winds towards the poles. The meandering wind stream moves towards the AP, resulting in the warming of this region. Additionally, this effect was found to be prominent in the winter months when the cyclones are more active. "We have shown that warm winter episodes in the Tasman Sea influence warm temperature anomalies over key regions of West Antarctica, including the AP, through a poleward shift of South Pacific cyclone tracks", Dr. Sato summarizes.
The ever-increasing warming of the AP--rather, the whole of Antarctica at large--is a major concern plaguing climatologists all over the world. Commenting on the serious implications of this rapid rise in temperature and sea levels and the importance of the findings of their study, Dr. Inoue says, "Antarctic warming accelerates Antarctic ice sheet melting and contributes to the rise in sea levels across the world. Therefore, knowledge of the mechanisms of the melting of the Antarctic ice sheet would help scientists, policymakers, and administrations to devise measures for people who will be most affected by the rising sea levels."
Dr. Sato and his team concludes by stating that the findings of their study can also aid the future forecast of ice sheet melting in Antarctica and consequent global sea level rise.
###
About Kitami Institute of Technology, Japan
Kitami Institute of Technology is a national university in Kitami, Hokkaido, Japan. It was founded as the Kitami Junior College of Technology on 1 April 1960 and it was chartered as a university on 1 April 1966. In 2004, it became part of the National University Corporation.
Website: https://www.kitami-it.ac.jp/en/
About Dr. Kazutoshi Sato from Katami Institute of Technology, Japan
Dr. Kazutoshi Sato is an Assistant Professor at Kitami Institute of Technology in Japan. He has worked as a Project Researcher at National Institute of Polar Research, Japan. His research group is interested in understanding climate variability and its effects on increasing sea levels.
About National Institute of Polar Research (NIPR)
The NIPR engages in comprehensive research via observation stations in Arctic and Antarctica. As a member of the Research Organization of Information and Systems (ROIS), the NIPR provides researchers throughout Japan with infrastructure support for Arctic and Antarctic observations, plans and implements Japan's Antarctic observation projects, and conducts Arctic researches of various scientific fields such as the atmosphere, ice sheets, the ecosystem, the upper atmosphere, the aurora and the Earth's magnetic field. In addition to the research projects, the NIPR also organizes the Japanese Antarctic Research Expedition and manages samples and data obtained during such expeditions and projects. As a core institution in researches of the polar regions, the NIPR also offers graduate students with a global perspective on originality through its doctoral program. For more information about the NIPR, please visit: https:/
About the Research Organization of Information and Systems (ROIS)
The Research Organization of Information and Systems (ROIS) is a parent organization of four national institutes (National Institute of Polar Research, National Institute of Informatics, the Institute of Statistical Mathematics and National Institute of Genetics) and the Joint Support-Center for Data Science Research. It is ROIS's mission to promote integrated, cutting-edge research that goes beyond the barriers of these institutions, in addition to facilitating their research activities, as members of inter-university research institutes.
Journal
Nature Communications