Satellite technology opens new window on Antarctica

This article is part of an exclusive article IEEE Journal Watch Series In partnership with IEEE Xplore.

Scientists have been diligently monitoring Earth's ice sheets via satellite imagery for decades, as the ice that covers the Earth's polar regions has a major impact on Earth's climate. However, these remote sensing methods have traditionally provided a general understanding of the extent of the ice, but little additional detail about the nature of the ice itself. Fortunately, new insights are emerging thanks to data from a Chinese satellite called Fengyun-3E (FY-3E), which allows scientists to determine whether Antarctic ice has formed over the past year or years. This helps us more accurately determine whether the

Antarctic sea ice extent was increasing until 2014, at which point it began to decline rapidly. The Antarctic ice that actually forms can survive summers and endure for years, but is subject to particularly harsh and dynamic factors, such as offshore winds and strong circumpolar currents. Therefore, Antarctic ice is more dynamic and difficult to classify compared to Arctic ice.

The launch of the FY-3E satellite in 2021 provided a unique means to assess Antarctic ice in more detail. The early morning orbiting weather satellite carries a number of tools, including WindRAD, an active dual-frequency, dual-polarization scatterometer. As the name suggests, it measures the scattering rate and characteristics of radar waves propagating through the atmosphere. FY-3E can also monitor the Earth's surface in a rotating fan-beam cone scan mode, detecting wind vector patterns on the ocean surface and properties of extreme sea ice.

Xiaochun Zhai, an associate professor at the China Meteorological Administration's National Satellite Meteorological Center in Beijing, is helping analyze data from WindRAD. “Her four signature parameters obtained from FY-3E WindRAD orbital observations can not only distinguish between sea ice and water, but also further distinguish between first-year ice and multi-year ice in Antarctica,” she said. I will explain.

In a study published last month, IEEE Earth Science and Remote Sensing Letter, Zhai's team has devised a method to use WindRAD data to infer the type of sea ice in Antarctica. They combined data from WindRAD with the only operational sea ice type product released by the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) and the multi-year ice product released by the Institute of Environmental Physics at the University of Bremen. concentration products, and the Russian Arctic and Antarctic Research Institute (AARI). This result shows that WindRAD can accurately distinguish between first-year Antarctic ice (sea ice whose growth has not exceeded its one winter) and multi-year ice (which has survived melting for at least one summer). suggests.

Zai says there are multiple benefits to being able to monitor Antarctic ice in such detail. “Observing and analyzing Antarctic sea ice types can improve our understanding of sea ice mass balance, heat flux between the ocean and atmosphere, polar circulation, and other processes in Antarctica,” she said. explained, and pointed out that these data could also be useful. We will continue to provide more accurate ice and climate models.

Zhai also points out that WindRAD's original purpose was to monitor a range of wind speeds and directions from space. Nevertheless, her team was able to extend the tool's original purpose and use its data to better understand Earth's polar regions. “This is an excellent example of expanding the detection capabilities of satellite microwave remote sensing,” Zai said.