A phenomenon that typically occurs every two to seven years, El Niño causes much warmer than average ocean temperatures in the eastern Pacific, significantly affecting weather around the globe.  

The Quelccaya Ice Cap (QIC) in the Peruvian Andes has been shown to be sensitive to these climate shifts, but the extent to which El Niño contributes to its continued shrinkage has, to date, been unclear. 

Now, using images captured by NASA Landsat satellites over the past four decades, researchers have confirmed that the regional warming periodically caused by El Niño has indeed resulted in a drastic reduction of its snow-covered area. The study, led by Kara Lamantia, a graduate student at the Byrd Polar and Research Climate Center at The Ohio State University, found that between 1985 and 2022, the QIC lost about 58% of its snow cover and about 37% of its total area. 

“Our research gives us a look into a glacier’s health,” said Lamantia. “The Quelccaya glacier becomes greatly out of equilibrium during these short-term climate anomalies.”

The study, published today (October 8, 2024) in the journal The Cryosphere, is the first to automate the process of snow-covered area detection on the QIC. Normally, this detection is only possible through extensive field measurements or manually hand-tracing satellite images that are clear enough to detail the visual boundary between snow and ice. 

Yet an algorithm this team developed processes images using near-infrared imagery, a method that utilizes wavelengths outside our visible spectrum. “By creating a threshold for the different reflectance between snow and ice cover, we can gather a consistent and much more reliable measurement,” said Lamantia. 

Glaciers and ice caps gain mass by accumulating ice and snow and lose it when none is received, or more ice is lost than gained. By measuring the ratio of snow-covered area to the total area, researchers can quantify whether the QIC is gaining mass, losing it, or maintaining a steady state. 

The study revealed that during El Niños, the ratio drops significantly away from the average, indicating a drastic reduction in the snow-covered area. 

This extreme change in its ratio may be attributed to the wide differences between the dry and wet seasons in southern Peru, said Lamantia.

“All of the snowfall happens during the wet season, but during an El Niño, southern Peru experiences warmer and drier conditions than average so it stays dry throughout the wet season,” she said. “That means that the snow cover will continue to decline and there might be quite a bit less snowfall to replace it.”

As climate change rapidly alters the Earth’s environment, it’s expected that El Niños are likely to be longer-lived and stronger, a factor that will accelerate ice loss. This raises the possibility of the QIC’s snow cover failing to recover during La Niñas, or periods when the oceans should be cool.

“The ice cap as a whole is on a very consistent linear decline from anthropogenic warming,” said Lamantia. “It may not matter how strong future La Niñas are, as the freezing line continues to rise and snow cover shrinks, Quelccaya will likely continue to decline.”

If this carries on, some projections suggest that snow cover on the QIC could disappear by 2080, relegating it to a wasting ice field, much like Kilimanjaro. By the end of the century, the study notes, the ice cap could be no more.

It’s difficult to discern how other short-term weather events might impact glacier vulnerability, which is something similar studies may aim to model in the future. What scientists do know is that ice loss puts high-mountain communities that depend on them in jeopardy, as snow loss can quickly diminish key water supplies. 

The damage already done to the oceans and atmosphere is not something we can reverse tomorrow, Lamantia said. Using the data collected about their complex interactions, researchers may have a better chance at monitoring and mitigating the planet’s climate woes.

“The general consensus is we can expect that the likely increased intensity and duration of El Niños will cause more complications for the QIC,” said Lamantia. “We need to start being clever about how we use and conserve our water resources.”

This study was supported by the National Science Foundation, the Heising-Simons Foundation and the Volo Foundation. Other co-authors were Lonnie Thompson and Bryan Mark from Ohio State and Laura J. Larocca of Arizona State University. 

By combining local weather data with complex astrophysics simulations, researchers explored whether a device that typically detects high-energy particles called muons could be used to remotely measure tornado-producing supercell thunderstorms. 

Conventional tornado-tracking instrumentation relies on measurements made by technologies like drones or weather balloons, but those methods often require humans to get dangerously close to the path of an oncoming storm. 

Yet through studying how these storms affect muons, which are heavier than electrons and travel through matter at nearly the speed of light, these findings can act as another tool for scientists to gain a more accurate picture of underlying weather conditions. 

“The thing about atmospheric muons is that they’re sensitive to the properties of the atmosphere that they travel through,” said William Luszczak, lead author of the study and a fellow at the Center for Cosmology and AstroParticle Physics at The Ohio State University. “If you have a group of muons that traveled through a thunderstorm, the amount you’re going to measure on the other side is different from a bundle of muons that traveled through a pretty day.”

The study was published on the open-access preprint server arXiv.

Compared to other cosmic particles, muons have many unique real-world applications, including helping scientists to peer inside large, dense objects like the pyramids or detecting hazardous nuclear material. Now, Luszczak’s simulations in this paper imply that supercell thunderstorms cause very slight changes in the number, direction and intensity of these particles. 

To determine this, the researchers applied a three-dimensional cloud model that could account for multiple variables, including wind, potential temperature, rain, snow and hail. Then, using atmospheric observations gathered from the 2011 supercell that passed through El Reno, Oklahoma, and spawned a tornado outbreak, Luszczak applied that information to measure variations in air pressure in the region around a simulated storm over the span of an hour. 

Overall, their results found that muons are indeed affected by the pressure field inside tornadoes, though more research is needed to learn more about the process.

In terms of how well it could work in the field, the concept is especially appealing, as utilizing muons to predict and analyze future weather patterns would also mean scientists wouldn’t necessarily have to try to place instruments very near a tornado to gain these pressure measurements, said Luszczak. 

Still, the type of muon particle detector that Luszczak’s paper considers is much smaller than other more well-known cosmic ray projects, such as the Pierre Auger Observatory in Argentina and the University of Utah’s Telescope Array. 

Unfortunately, these detectors don’t reside in places where they can study tornadoes, said Luszczak, but if placed in a region like Tornado Alley in the United States, researchers imagine that the device could easily complement typical meteorological and barometric measurements for tornadic activity. 

That said, the device’s size also influences how precise its measurements are, as scaling it up enhances the number of particles it can detect, said Luszczak. 

The smallest detector researchers describe in this paper is 50 meters across, or about the size of five buses. But while such a tool would be portable enough to ensure scientists could place it near many different types of storm systems, being so small would likely cause it to face some errors in its data-gathering, said Luszczak. 

Despite these potential setbacks, as supercell thunderstorms typically form and disappear in short periods, the paper emphasizes it may be well worth future scientists’ time to consider implementing a large detector in some regions – one that would likely be a permanent stationary establishment to catch as many muons as possible during severe weather events. 

More importantly, because current weather modeling systems are directly linked to when and where severe weather alerts are issued, using cosmic rays to strengthen those models would give the public a more detailed sense of a storm’s various twists and turns as well as more time to prepare for the phenomenon.  

“By having better measurements of the atmosphere surrounding a tornado, our modeling improves, which then improves the accuracy of our warnings,” said Luszczak. “This concept has a lot of promise, and it’s a really exciting idea to try to put into action.”

Leigh Orf of the University of Wisconsin-Madison was a co-author.  

Dubbed the extremely large telescopes (ELTs), these observatories, which include the Extremely Large Telescope (ELT), the Giant Magellan Telescope (GMT), and the Thirty Meter Telescope (TMT), will be some of the largest ground-based telescopes ever built, and their instruments are expected to exceed the capabilities of the James Webb Space Telescope.

Data collected with their powerful instruments will allow astronomers to use Doppler Imaging – a technique that can recreate 2D maps of an object’s surface – to make accurate measurements of the magnetism and chemistry of ultracool targets, or cosmic objects with temperatures less than 2700 K, such as brown dwarfs (BDs) or very low-mass stars (VLMs) –  and even some exoplanets.

Besides helping to improve our understanding of some of the most mysterious objects in the universe, having the capability to study the chemical compositions of these objects in a more precise manner also offers greater insight into the search for life on other worlds, said Michael Plummer, lead author of the study and a graduate student in astronomy at The Ohio State University.

“Learning about the atmospheres of other objects outside our solar system not only informs us how Earth’s atmosphere may behave but allows scientists to scale those concepts to study potentially habitable planets,” said Plummer.

The study was published this month in The Astrophysical Journal. 

Magnetism is especially important to search for worlds similar to our own as magnetic fields, specifically for smaller star systems, are considered necessary to support and influence whether a planet can support life on its surface.  

To aid in this hunt, Plummer and Ji Wang, co-author of the study and an assistant professor of astronomy at Ohio State, previously developed a publicly available analytical code called Imber to simulate and infer the presence of surface discrepancies like magnetic star spots, cloud systems, and other atmospheric phenomena such as hurricanes on distant objects.

In this study, they used the technique to estimate the scientific capabilities of various ELTs’ instruments to detect surface variations on six targets: the star of Trappist-1, a well-studied seven-planet system about 40 light-years from Earth, two brown dwarfs, and three exoplanets.        

They used their technique to investigate the abilities of the following instruments: the GMT’s Consortium Large Earth Finder (GMT/GCLEF), the ELT’s Mid-Infrared ELT Imager and Spectrograph (ELT/METIS) and the TMT’s Multi-Objective Diffraction-limited High-Resolution Infrared Spectrograph (MODHIS).

Researchers found that while discerning star spots on Trappist-1 was challenging for all three instruments due to its edge-on inclination – or its orbit in parallel to the rest of the sky – ELT and TMT could make high-resolution observations of the brown dwarfs and exoplanets over a single rotation. 

Conversely, GMT’s instruments required multiple rounds of observations to determine the presence of surface irregularities on the study’s chosen exoplanets. Overall, the study shows that their technique can provide an accurate estimation of ELTs future abilities and help determine if future targets would be worth investigating on a larger scale. 

Plummer also said their technique garnered interest from scientists looking to identify or confirm planetary bodies found using the radial velocity method – a way to find exoplanets by studying the slight gravitational effect an object has on the star it orbits. In essence, their research is the first step towards helping scientists use future astronomical instruments to the best of their abilities.

“The more we learn about other similar planets to Earth, the more those discoveries should inform Earth science itself,” said Plummer. “Our work is particularly well-suited to help make those real-world observations.”

The study was supported by the National Science Foundation.