Ants are perhaps the unlikely heroes when it comes to better understanding the health of our planet in the midst of a climate crisis. In an article published at Frontiers of remote sensinga team of scientists, including those at NASA, have found a way to estimate snow depth from orbit using ants deep underground.
One of the team members is Yongxiang Hu of NASA’s Langley Research Center who drew inspiration from physics and biology to create a unique snow depth model. A previously developed model found that the average time an ant wanders inside the colony before returning is about four times the volume of the colony divided by its area.
The photon moves like ants in the colonies
“I studied the properties of clouds and learned that light bounces among cloud particles in a random way, similar to the movement of ants inside their colony. So, I thought that the ant theory could also apply to snow since snow comes from clouds,” Hu explained.
In the same way that an ant enters the colony and moves randomly before exiting, a photon of light from a lidar instrument penetrates the snow and is scattered when it encounters the snow particles until until it comes out and is detected by the telescope on ICESat-2 (Ice, Cloud and Land Uplift Satellite-2).
By applying a special model simulation to verify an equation similar to that used to estimate the distance traveled by an ant in a colony, the researchers found that it was possible to measure the average distance traveled by a photon in snow. This showed that the snow thickness was about half the average distance traveled by the photon inside the snow.
Ice and snow: the indissoluble bond
Launched in 2018, ICESat-2 aimed to determine the depth of Earth’s snow-capped ice caps and sea ice. Historically, measuring snow depth has proven difficult because it required consolidating lidar with microwave measurements.
With this new innovation used to measure the thickness of snow cover covering sea ice surfaces and mountains, scientists can get a clearer picture of how the climate crisis is affecting sea ice thickness as well as the thickness of glaciers on earth.
“Snowpack provides water resources to many regions, including the western United States and parts of Europe, Africa and Asia. Snow depth, as well as estimated snow density, are important for water resource management,” Hu added.
How much will the snowfall decrease?
Snow plays an important role in climate regulation because it reflects solar energy back into space and helps keep the planet cool. Less snow on the ground equals less reflectivity and more global warming.
Although precipitation is relatively easy to predict and climate models consistently predict an increase in global precipitation of between 3% and 7%, estimating how snowfall may decrease in mid-latitude regions due to global warming is much more complex. This is where this new technique will make the difference.
Hu has worked with other scientists from NASA, the University of Arizona, Stevens Institute of Technology and Ball Aerospace and hopes climate scientists will increasingly adopt the properties of snow derived from this robust technique. based on physics to make their predictions.
“I am confident that this technique will revolutionize the way we predict future snow evolution and model sea ice changes, and we are already working on designing the next generation of satellites specifically for the snow depth,” Hu said.
Frontiers of remote sensing
The title of the article
Derivation of snow depth from ICESat-2 Lidar multiple scattering measurements
Publication date of articles
Conflict of Interest Statement
Authors CW and JL were employed by Ball Aerospace Corp. The other authors declare that the research was conducted in the absence of any commercial or financial relationship which could be interpreted as a potential conflict of interest.
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