Warm, moist air currents can have a continent-wide impact and influence climate change
IMAGE: A BAND OF CLOUDS IN AN ATMOSPHERIC RIVER THAT DIVIDES FROM SOUTH AMERICA TO THE ANTARCTIC SEA ICE ZONE ON SEPT. 16, 2017. View More CREDIT: NASA
Warm, humid air flows in Antarctica play a key role in the formation of massive holes in the sea ice in the Weddell Sea and, according to research co-authored by Rutgers, can influence ocean conditions on the vast continent and climate change.
Scientists studied the role of long, intense plumes of warm, moist air – known as atmospheric rivers – in creating enormous openings in sea ice. They focused on the Weddell Sea region of the Southern Ocean near Antarctica, where these sea ice holes (called polynyas) rarely develop in winter. A large hole in this area was first observed in 1973 and another hole developed in late winter and spring 2017.
In the first of its kind, published in the journal Science Advances, scientists found that repeated strong atmospheric flows from late August to mid-September 2017 played a crucial role in the formation of the sea ice hole. These rivers brought warm, moist air from the coast of South America into the polar environment, warming the sea ice surface and making it prone to melting.
"Polynyas have a profound impact on the physical and environmental dynamics of the Southern Ocean," said co-author Kyle Mattingly, a postdoctoral fellow at the Rutgers Institute of Earth, Ocean and Atmospheric Sciences. “They serve as huge“ windows ”in the sea ice, through which large amounts of heat from the ocean enter the atmosphere and change the regional and global ocean circulation. They also affect the timing and size of the phytoplankton blooms (algae) that form the basis of the marine food web. Our study will pave the way for a better understanding of climate variability and climate change in these regions. "
Previous studies have shown that atmospheric rivers affect the melting of land ice and ice shelf in West Antarctica, and the new study builds on these findings by showing their effects on Antarctica sea ice for the first time. The rivers are thousands of miles long and the sea ice holes cover thousands of square miles, usually in specific locations prepared by the local ocean circulation conditions.
West Antarctica, a huge sheet of ice lying on land, is melting and contributing to the global rise in sea levels. The melt has accelerated in the 21st century. If the entire ice sheet of Antarctica were to melt, sea levels would rise about 200 feet, according to the National Snow & Ice Data Center. Sea level rise and flooding from coastal storms threaten coastal communities around the world, especially in lower-lying areas.
Under the predicted future climate change, it is predicted that atmospheric rivers will become more frequent, longer, wider and more effective in transporting high amounts of water vapor towards the Antarctic Ocean and continent while increasing the intensity of precipitation. Landing is generally predicted to shift towards the poles and the effects of climate change on sea ice holes in the Weddell Sea and elsewhere in the Southern Ocean are an important area for future research.
Co-authors include scientists from the Khalifa University of Science and Technology, the Stevens Institute of Technology and the Australian Antarctic Division, and the Australian Antarctic Program Partnership.