Drone Technology Exposes Alarming Changes in Greenland Ice Sheet

Excessive over the frozen floor of Greenland, a brand new instrument is rewriting what scientists learn about how water strikes by the Arctic sky. A drone, outfitted with customized devices, has offered the primary high-resolution have a look at water vapor and its isotopic fingerprints above one of many world’s largest ice sheets. The findings are revealing a extra complicated water cycle than beforehand understood—one which will form future sea stage rise.

Researchers flew the fixed-wing drone 104 instances throughout summer time 2022 from the East Greenland Ice-Core Undertaking camp, a distant web site in northeast Greenland. Their mission: to measure the air’s water vapor and analyze its isotopes, the marginally totally different variations of hydrogen and oxygen that make up water molecules. These delicate variations act like fingerprints, providing clues about the place water got here from and the way it modified on its journey by the environment.

Water is continually biking by the planet—evaporating, freezing, sublimating, and condensing. Throughout these modifications, its isotopic composition shifts in ways in which mirror temperature, humidity, and mixing with different air lots. These shifts are recorded in snow, ice, and vapor, making isotopes a robust instrument for reconstructing previous local weather and enhancing future fashions.

But, till now, scientists have had little entry to isotope knowledge from the air above Greenland. Conventional plane missions are pricey and dangerous within the Arctic, and ground-based towers can solely pattern as much as 25 meters above the floor. That left a big knowledge hole stretching as much as the decrease troposphere, the place a lot of the vapor change occurs.

“It’s like we simply found out how one can uncover fingerprints at against the law scene,” stated Kevin Rozmiarek, a doctoral researcher on the Institute of Arctic and Alpine Analysis at CU Boulder and lead writer of the new study. “This can be a concrete step ahead in understanding the place water goes and the place it’s coming from on this vital system at a time after we want it most.”

To fill the hole, Rozmiarek and his crew turned to a big drone with a 10-foot wingspan. They loaded it with delicate devices to seize air samples and measure meteorological knowledge like temperature and humidity. Every flight reached as excessive as 1,500 meters—or practically 5,000 toes—above the ice sheet.

In tandem, the crew additionally collected snow samples each 12 hours at floor depths of 1 cm and 5 cm. These twin knowledge units allowed them to hyperlink airborne water vapor to floor snow, constructing a extra full image of how water strikes out and in of Greenland’s ice.

One main benefit of utilizing isotopes is their means to seize the historical past of part modifications—like evaporation and sublimation—that standard weather variables miss. Temperature, strain, and humidity don’t totally clarify how water behaves within the Arctic’s excessive situations. However isotopes maintain a “reminiscence” of the place the vapor got here from and what it skilled alongside the best way.

“Isotopes are water’s fingerprints,” Rozmiarek stated. “By following these fingerprints, we are able to hint again to the supply the place the water vapor got here from.”

Greenland holds about 8% of the world’s freshwater. Since 1992, it has misplaced greater than 5 trillion tons of ice. Between fall 2023 and fall 2024 alone, the island misplaced about 55 gigatons of ice and snow, based on the National Oceanic and Atmospheric Administration. It marks the twenty eighth straight yr of web ice loss.

Most of this loss comes from melting and calving—when large chunks of glaciers break into the ocean. However one other much less seen course of, sublimation, could play a bigger function than as soon as thought. Sublimation happens when snow turns straight into vapor, skipping the liquid stage.

One research from the buildup zone of the ice sheet discovered that as a lot as 31% of snow deposited throughout the summer time sublimated reasonably than melting or compacting into ice. However what occurs to that vapor stays unclear. Does it fall again as snow? Recondense on the floor? Or depart the area completely?

The brand new drone knowledge means that fashions could underestimate how a lot vapor escapes from Greenland. The crew in contrast their observations with an current local weather mannequin and located that the mannequin didn’t account for sufficient water being faraway from the atmosphere earlier than it reached the ice sheet. When the crew adjusted the mannequin utilizing the isotope knowledge, predictions of precipitation and moisture transport improved considerably.

“We demonstrated how helpful water vapor isotope knowledge is by efficiently enhancing an current mannequin,” Rozmiarek stated.

Correct fashions are essential for projecting future ice loss and sea stage rise. However modeling how water behaves over ice sheets is hard, particularly when observations are missing. Most water vapor isotope research have targeted on decrease latitudes, the place it’s simpler to fly crewed plane.

Within the Arctic, the bodily processes are totally different. Floor sublimation, katabatic winds—chilly, dense air flowing downhill—and excessive temperature inversions all play a job in shaping moisture pathways. But few fashions are tuned to seize these distinctive components.

Within the drone research, the crew used a Lagrangian backtrajectory mannequin paired with a water distillation simulator known as HySPLIT-SWIM. Whereas the mannequin matched observations for temperature and humidity nicely—inside a imply distinction of simply +0.095°C and −0.043 g/kg—it struggled to copy the isotope profiles.

The discrepancy beneath the 200-meter inversion layer pointed to a probable trigger: kinetic fractionation. This course of happens when totally different isotopes behave otherwise throughout part modifications and mixing. The drone knowledge confirmed indicators of vapor from sublimated snow mixing with katabatic winds, creating a posh isotopic sign not totally captured by the mannequin.

“This end result requires substantial future evaluation of kinetic fractionation processes alongside all the moisture pathway,” the researchers famous.

Understanding how a lot vapor leaves Greenland is vital to measuring its water funds. Earlier proof from snow pits confirmed that sublimated snow might affect the isotope make-up of recent snow downwind. However direct measurements of atmospheric vapor and its hyperlink to the snow floor have been lacking.

Now, with drone-based isotope profiling, scientists can start to shut that loop. By capturing knowledge from each the supply (tropical moisture) and the sink (floor snow), researchers are lastly in a position to examine the in-between: the shifting vapor that connects them.

This issues as a result of if sublimated vapor is misplaced to the environment and never recycled domestically, it means extra freshwater is leaving the Greenland system than beforehand counted. That loss might speed up sea stage rise, disrupt ocean currents, and reshape ecosystems throughout the globe.

About 125,000 years in the past, throughout a heat interval, Greenland’s ice sheet was smaller, and international sea ranges have been as much as 19 toes larger. Right this moment, with rising temperatures and melting ice, scientists warn the identical might occur once more—this time pushed by human-caused warming.

The drone research is only the start. Rozmiarek and his crew plan to return to Greenland and develop their flights to different Arctic regions. Their objective is to construct a bigger knowledge set that may inform higher fashions, information local weather projections, and monitor the water cycle in actual time.

“There’s nonetheless a lot we don’t know,” Rozmiarek stated. “We can perceive how water strikes out and in of Greenland within the subsequent few years.”

With the Arctic warming quicker than anyplace else on Earth, each new perception issues. By tracing the invisible fingerprints of water within the sky, scientists are uncovering clues that might reshape how we put together for a future formed by ice, vapor, and a warming world.