“Drones Uncover Changes in Greenland Ice Sheet Using Advanced Technology”
High above Greenland’s icy terrain, a revolutionary tool is revolutionizing scientists’ understanding of water movement in the Arctic. A drone, equipped with specialized instruments, has provided a detailed examination of water vapor and its isotopic characteristics above one of the world’s largest ice sheets. The insights gained are shedding light on a more intricate water cycle than previously known, one that could influence future sea level rise.
Throughout the summer of 2022, researchers operated the fixed-wing drone on 104 missions from the East Greenland Ice-Core Project camp, situated in remote northeast Greenland. Their objective was to measure water vapor in the air and analyze its isotopes, which are variations of hydrogen and oxygen present in water molecules. These isotopic distinctions act as unique markers, offering insights into the origin and transformation of water as it traverses the atmosphere.
Water’s journey through the planet involves a continuous cycle of evaporation, freezing, sublimation, and condensation. During these transitions, its isotopic composition undergoes changes that reflect factors such as temperature, humidity, and interactions with other air masses. These changes are recorded in snow, ice, and vapor, making isotopes a valuable tool for reconstructing past climates and enhancing future climate models.
However, data on isotopes from the airspace above Greenland has been limited until now. Conventional aircraft missions in the Arctic are expensive and risky, while ground-based towers can only sample close to the surface. This left a significant data gap in the lower troposphere, where crucial vapor exchanges occur.
In a breakthrough approach, Kevin Rozmiarek, a doctoral researcher at the Institute of Arctic and Alpine Research at CU Boulder, and his team employed a large drone with a 10-foot wingspan. Fitted with precise instruments for air sampling and meteorological data collection, each flight reached heights of up to 1,500 meters above the ice sheet.
Additionally, the team gathered snow samples every 12 hours at depths of 1 cm and 5 cm on the surface. By correlating airborne water vapor with surface snow data, they developed a more comprehensive understanding of water movements in and out of Greenland’s ice.
An advantage of using isotopes is their ability to capture the history of phase changes, such as evaporation and sublimation, which conventional weather variables may overlook. With their unique “memory” of vapor origins, isotopes provide a deeper insight into water behaviors in the extreme Arctic conditions.
“Isotopes act as unique markers in water,” explained Rozmiarek. “By tracking these markers, we can identify the origin of water vapor.” As the Climate Shifts, Greenland’s Ice MeltsGreenland contains approximately 8% of the world’s freshwater. Since 1992, it has lost over 5 trillion tons of ice. In just one year, from fall 2023 to fall 2024, the island shed about 55 gigatons of ice and snow, as reported by the National Oceanic and Atmospheric Administration. This marks the 28th consecutive year of net ice loss.A drone touched down on the snow-covered surface of Greenland at EastGRIP. Most of the ice loss is attributed to melting and calving—when large glacier chunks break off into the ocean. However, another less visible process, sublimation, may have a more significant impact than previously believed. Sublimation occurs when snow transforms directly into vapor, bypassing the liquid stage.A study conducted in the accumulation zone of the ice sheet revealed that up to 31% of the summer-deposited snow sublimated instead of melting or turning into ice. Nevertheless, the fate of this vapor remains uncertain. Does it return as snow, recondense on the surface, or exit the region entirely? Recent drone data suggests that current models may underestimate the amount of vapor escaping from Greenland. By comparing their findings with an existing climate model, the team discovered that the model did not consider enough water being extracted from the atmosphere before reaching the ice sheet. Adjusting the model with isotope data significantly enhanced predictions of precipitation and moisture transport.“We showcased the value of water vapor isotope data by enhancing an existing model successfully,” Rozmiarek remarked. A bird’s eye view of the EGRIP camp area. The regions where UAS data (“Flight area”), vapor measurements, and snow samples were collected are delineated. The Arctic Moisture Modeling ConundrumAccurate models are essential for projecting future ice loss and sea-level rise. However, predicting how water behaves over ice sheets is challenging, particularly when observations are scarce. Most studies on water vapor isotopes have centered on lower latitudes, where it is simpler to pilot manned aircraft.The Arctic presents distinct physical processes. Surface sublimation, katabatic winds (cold, dense air descending downhill), and extreme temperature inversions all influence moisture pathways. Yet, few models are fine-tuned to capture these unique elements.In the drone study, the team combined a Lagrangian backtrajectory model with a water distillation simulator named HySPLIT-SWIM. While the model closely aligned with observations for temperature and humidity—within an average difference of merely +0.095°C and −0.043 g/kg—it struggled to replicate the isotope profiles.The mismatch below the 200-meter inversion layer indicated a probable cause: kinetic fractionation. This phenomenon arises when different isotopes behave differently during phase changes and mixing.
Measuring Greenland’s Water Cycle: The Importance of Isotope Profiling
The investigation of Greenland’s water cycle is crucial for understanding its water budget. Previous studies using snow pits revealed that sublimated snow could impact the isotopic composition of new snow downwind. However, direct measurements linking atmospheric vapor to the snow surface were lacking. Thanks to drone-based isotope profiling, scientists can now bridge this gap. By collecting data from both the moisture source (tropical) and the snow surface, researchers are able to study the intermediate process: the moving vapor that connects them.
This research is significant because if sublimated vapor escapes into the atmosphere rather than being locally recycled, it implies that more freshwater is leaving Greenland than previously accounted for. This loss could contribute to accelerated sea level rise, disrupted ocean currents, and ecosystem changes worldwide. Approximately 125,000 years ago, during a warm period, Greenland’s ice sheet was smaller, resulting in global sea levels rising up to 19 feet. Today, with increasing temperatures and ice melt, scientists warn that a similar scenario could occur again, driven by human-induced warming.
The drone study marks the beginning of a new approach. Rozmiarek and his team plan to conduct further flights in Greenland and other Arctic regions to expand their dataset. Their aim is to enhance models, improve climate projections, and monitor the water cycle in real time. “There is still much we have yet to discover,” Rozmiarek noted. “In the coming years, we will gain insights into how water flows in and out of Greenland.”
Given the rapid warming of the Arctic compared to other regions, each new finding is critical. By tracing the subtle water signatures in the atmosphere, scientists are unraveling clues that could reshape our readiness for a future shaped by ice, vapor, and a changing climate.
