A Sandia study used never-before-seen data from GPS monitors to learn more about what’s decreasing the sun’s reflectivity in the Arctic, which is warming faster than anywhere else on Earth. Credit: Valérie Sparks
The Arctic, Earth’s ice crown, is experiencing an unprecedented climate crisis. It is warming at a rapid rate, four times faster than the rest of our planet. Sandia researchers are lifting the curtain on reduced sunlight reflectivity, or albedo, that is accelerating Arctic warming.
Scientists are not armed with parkas or shovels. Instead, they leveraged data from GPS satellites’ radiometers, capturing sunlight bouncing off the Arctic. This data dive could be the key to cracking the Arctic amplification code.
Their work is published in the journal Scientific reports.
“The uneven warming of the Arctic is both a scientific curiosity and a pressing concern, leading us to question why this landscape has changed so dramatically,” said Erika Roesler, an atmospheric and climate scientist at Sandia.
Previous studies have suggested that sea ice albedo feedbacks are likely driving the Arctic amplification. These albedo feedbacks can be divided into two main areas. First, there is an overall reduction in sea ice, leading to greater exposure of the dark ocean, which absorbs more sunlight than snow-covered ice, causing temperatures to rise. The second factor is the reflectivity of the remaining sea ice, or local albedo, which includes the accumulation of water on the ice due to melting.
Sandia researchers aimed to better understand the reduction in reflectivity in the Arctic. Principal scientist Phil Dreike worked with the U.S. Space Force to obtain permission from Sandia to analyze previously unpublished data from GPS satellite radiometers.
“The new observational climate datasets are unique. To qualify as a climate dataset, observations must span a multitude of years. Small-scale science projects typically don’t last that long, this which makes this dataset particularly valuable,” Roesler said.
Amy Kaczmarowski, an engineer at Sandia, conducted an analysis of data spanning 2014 to 2019.
“There have been many local measurements and theoretical discussions regarding the effects of puddles on ice albedo. This study represents one of the first comprehensive examinations of year-to-year effects in the region Arctic,” Kaczmarowski said.
“Analysis of Sandia data revealed a 20 to 35 percent decrease in total reflectivity during the Arctic summer. According to microwave sea ice extent measurements collected during the same period, a third of this loss of reflectivity is attributed to completely melted ice.
The remaining two-thirds of the reflectivity loss is likely caused by weathering of the remaining sea ice. “The key finding here is how much weathered ice reduces reflectivity,” Kaczmarowski added. Weathered ice refers to remaining sea ice, which may be thinner and contain melting pools.
GPS satellites are expected to continue providing data through 2040. Sandia researchers hope other researchers will take their findings and incorporate them into their Arctic amplification models. They plan to continue mining the GPS data and are excited to collaborate with other climate scientists for further analysis.
“We will continue to use these data to study various regions of Earth for climate applications,” Kaczmarowski said.
More information:
Philip L. Dreike et al, Broadband radiometric measurements from GPS satellites reveal that summer Arctic Ocean albedo declines faster than sea ice retreats, Scientific reports (2023). DOI: 10.1038/s41598-023-39877-x
Provided by Sandia National Laboratories
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