There is no climatic disaster like the one afflicting the Arctic, the ice on top of Earth. It is warming up four times more quickly than the rest of the globe. The decrease in sunlight reflectivity, or albedo, which is accelerating the warming of the Arctic, is being revealed by researchers at Sandia National Laboratories.
The scientists do not carry shovels and parkas. Instead, they have used information from GPS satellite radiometers to record sunlight reflected off the Arctic. This data dive could be the key to unlocking the mystery of the Arctic amplification.
The uneven warming in the Arctic is both a scientific curiosity and a pressing concern, leading us to question why this landscape has been changing so dramatically.
Erika Roesler, Atmospheric and Climate Scientist, Sandia National Laboratories
According to earlier research, sea-ice albedo feedbacks are probably responsible for Arctic amplification. There are two primary categories for this albedo feedback. First, there is a general decrease in sea ice, which increases the amount of the dark ocean exposed. This increases the temperature because it absorbs more sunlight than ice coated in snow.
The second component is the local albedo, or reflection of the remaining sea ice, which includes water that has accumulated on the ice as a result of melting.
The goal of the Sandia research team was to learn more about why reflectance is declining in the Arctic. Senior scientist Phil Dreike worked with the US Space Force to secure authorization for Sandia to examine data from GPS satellite radiometers that had not been released before.
Roesler added, “New observational climate datasets are unique. To qualify as a climate dataset, observations must span a multitude of years. Small-scale science projects are typically not that long in duration, making this dataset particularly valuable.”
An engineer at Sandia named Amy Kaczmarowski examined the information from 2014 to 2019.
There have been numerous local measurements and theoretical discussions regarding the effects of water puddling on ice albedo. This study represents one of the first comprehensive examinations of year-to-year effects in the Arctic region. Sandia’s data analysis revealed a 20% to 35% decrease in total reflectivity over the Arctic summer. According to microwave sea-ice extent measurements collected during the same period, one-third of this loss of reflectivity is attributed to fully melted ice.
Amy Kaczmarowski, Graduate Student, University of Wisconsin-Madison
The deterioration of the remaining sea ice is probably responsible for the remaining two-thirds of the reflectance loss.
Kaczmarowski added, “The key discovery here is just how much the weathered ice is reducing reflectivity.”
The surviving sea ice, which may be thinner and include melt ponds, is referred to as “weathered ice.”
It is anticipated that the GPS satellites will keep sending out data until 2040. The Sandia group is hoping that other scientists will take a look at their findings, which they recently published in the Nature Scientific Reports journal, and apply them to their models of Arctic amplification. They are eager to work with other climate experts to do more study, and they want to keep mining the GPS data.
Kaczmarowski concluded, “We will continue to use this data to investigate various regions of the Earth for climate applications.”
Dreike, P. L., et. al. (2023) Broadband radiometric measurements from GPS satellites reveal summertime Arctic Ocean Albedo decreases more rapidly than sea ice recedes. Scientific Reports. doi:10.1038/s41598-023-39877-x