Scientists may have solved a 2,000-year-old Dead Sea Scrolls mystery

 A longstanding mystery surrounding the Dead Sea Scrolls may have a new explanation. Researchers have debated for decades whether the Qumran sect actually followed its unusual 364-day calendar or whether the system existed mainly as a religious and theoretical ideal.

A study from Tel Aviv University argues that both possibilities may be partly correct. According to the proposed reconstruction, the sect likely used the calendar during its early history, when disagreements over religious dates contributed to its separation from the Jerusalem establishment. Later, however, the system may have been abandoned because of a fundamental astronomical problem and changing political relations with the Hasmonean leadership under Alexander Jannaeus.

The research was conducted by Prof. Eshbal Ratzon of the Department of Jewish Philosophy and the Cohn Institute for the History and Philosophy of Science and Ideas at the Entin Faculty of Humanities. The findings were published in the Tarbiz Quarterly for Jewish Studies.

A Calendar Built Around 52 Perfect Weeks

The Qumran calendar differed sharply from the lunisolar calendar that shaped Jewish religious life during the Second Temple period.

Its year contained exactly 364 days, which can be divided evenly by seven. That produced 52 complete weeks every year and ensured that religious festivals always occurred on the same day of the week.

For members of the Qumran sect, this orderly structure was more than a mathematical convenience. They regarded it as reflecting a perfect divine system.

The calendar also carried political and religious significance. Authorities at the Temple in Jerusalem determined important dates using the prevailing calendar, but the Qumran sect rejected the idea that human leaders should have that power. Its members believed the dates had already been established by God during the Creation of the world and therefore should not be altered by people.

The Hidden Problem With 364 Days

The very feature that made the Qumran calendar so elegant also created a serious practical problem.

A 364-day year is about one day and a quarter shorter than the roughly 365-day astronomical year. That discrepancy seems small at first, but it grows steadily over time.

If the system were followed for twenty years without correction, religious festivals would shift by almost four weeks relative to the seasons. After several decades, a festival associated with spring could eventually fall in winter or even autumn.

That would have been especially troublesome for a community whose religious festivals were closely connected with agriculture, harvests, first fruits, and the seasonal cycle.

The problem can be compared with a clock that loses one minute every day. The error is barely noticeable at first, but after enough time passes, the clock no longer reflects the actual time.

Prof. Ratzon's study suggests that something similar may have happened with the Qumran calendar. Although the system was conceptually elegant and mathematically orderly, it gradually drifted farther away from the natural seasonal cycle it was meant to organize.

Was the Calendar Ever Really Used?

Scholars have offered several explanations for this puzzle over the years.

Some have proposed that the Qumran community periodically inserted additional days or weeks to keep the calendar aligned with the seasons. Others have argued that the 364-day system was never intended for everyday use and functioned only as an idealized religious framework.

Prof. Ratzon argues that the Dead Sea Scrolls do not clearly support either explanation.

Instead, she points to evidence suggesting that the calendar was deeply important to the sect's religious identity and formed a major part of its disagreement with the religious authorities in Jerusalem.

Nearly twenty scrolls discovered at Qumran address calendars and astronomy, an unusually large number that indicates how significant these subjects were to the community.

The Book of Jubilees, one of the important works preserved in the Qumran library, strongly criticizes the prevailing lunar calendar. It presents the 364-day system as the original calendar given to Moses on Mount Sinai.

A Calendar at the Center of a Religious Conflict

Drawing on this evidence, Prof. Ratzon proposes a different historical scenario.

She argues that the Qumran sect actively followed the 364-day calendar during its formative period in the second century BCE. The dispute over how sacred time should be measured may have intensified the sect's conflict with religious leaders in Jerusalem and contributed to its isolation.

But as the decades passed, the growing mismatch between the calendar and the seasons would have become increasingly difficult to ignore.

Source: ScienceDaily

8 common food additives linked to high blood pressure and heart disease

 Common food preservatives found across the processed food supply may be associated with a greater risk of high blood pressure and cardiovascular disease, according to research published in the European Heart Journal.

The study was led by Dr. Mathilde Touvier, a research director at INSERM (the French National Institute for Health and Medical Research), and Anaïs Hasenböhler, PhD student, both from the Nutritional Epidemiology Research Team at the Université Sorbonne Paris Nord and Université Paris Cité, France.

Preservatives are added to foods for several reasons, including preventing the growth of bacteria and mold, slowing spoilage, and helping products maintain their color, flavor, or freshness for longer. Because these ingredients are so widely used, researchers wanted to better understand whether long-term exposure could be connected to cardiovascular health.

Ms. Hasenböhler said: "Food preservatives are used in hundreds of thousands of industrially processed foods. Experimental studies suggest that some preservative food additives may be harmful to cardiovascular health, but we have not had enough evidence on the impact of these ingredients in humans. As far as we know, this is the first study of its kind to investigate the links between a wide range of preservatives and cardiovascular health."

Tracking Diet and Heart Health in More Than 112,000 People

The work was conducted as part of NutriNet-Santé, a large ongoing research project examining the connections between nutrition and health. The analysis included 112,395 volunteers living across France.

Every six months, participants recorded everything they ate and drank during a three-day period. This gave researchers unusually detailed information about their diets rather than relying only on broad estimates of food consumption.

The research team then examined the ingredients in those foods and beverages, including the preservatives they contained. Participants were followed for an average of seven to eight years so researchers could track whether they developed high blood pressure or cardiovascular diseases such as heart attack, stroke, or angina.

Preservative exposure was nearly universal. During the first two years of participation, 99.5% of the volunteers consumed at least one food preservative.

Higher Preservative Intake Linked to Higher Risk

The strongest associations appeared among people consuming the largest amounts of certain preservatives.

Participants with the highest intake of 'non-antioxidant' preservatives had a 29% higher risk of hypertension than those consuming the lowest amounts. They also had a 16% higher risk of cardiovascular disease, which included heart attack, stroke and angina.

People who consumed the greatest amounts of antioxidant preservatives had a 22% higher risk of hypertension.

The two categories protect food in different ways. Non-antioxidant preservatives are generally used to prevent potentially harmful microorganisms, including bacteria and mold, from growing. Antioxidant preservatives instead slow oxidation, a chemical process that can cause foods to brown, develop unpleasant flavors, or become rancid.

Eight Common Preservatives Stood Out

Researchers also analyzed 17 of the preservatives most commonly consumed by participants.

Eight were specifically associated with a higher risk of high blood pressure: potassium sorbate (E202), potassium metabisulphite (E224), sodium nitrite (E250), ascorbic acid (E300), sodium ascorbate (E301), sodium erythorbate (E316), citric acid (E330) and extracts of rosemary (E392).

Ascorbic acid (E300) was also specifically associated with cardiovascular disease.

These findings do not mean that consuming one of these ingredients will necessarily cause high blood pressure or heart disease. The research was observational, meaning it identified statistical associations rather than proving that preservatives were directly responsible for the increased risks.

Dr. Touvier added: "This study has some limitations inherent to its observational design. However, the findings are based on highly detailed data, and we have taken account of other factors that can increase or lower the risk of cardiovascular disease. Experimental research in the literature consistently suggested that preservatives may cause oxidative stress in the body or affect the way the pancreas works.

"These results suggest we need a re-evaluation of the risks and benefits of these food additives by the authorities in charge, such as the EFSA in Europe and the FDA in the USA, for better consumer protection. In the meantime, these findings support existing recommendations to favor non-processed and minimally processed foods, and avoid unnecessary additives. Doctors and other healthcare professionals play a key role in explaining these recommendations to the public."

Source: ScienceDaily

Millions take calcium and vitamin D for bone health. A major review finds little benefit

 Calcium and vitamin D supplements are widely taken to support bone health, especially by older adults. But a large review published in The BMJ suggests that, for most older people, these supplements provide little to no meaningful protection against falls or broken bones.

Falls are a major health concern as people age. Nearly one in three adults aged 65 and older falls each year, and those falls can lead to fractures, chronic pain, loss of independence, reduced quality of life, and in some cases a move into residential care. Finding effective ways to prevent falls and fractures is therefore an important public health goal.

Longstanding Questions About Bone Supplements

Calcium and vitamin D have long been associated with bone health. Calcium is a major structural component of bone, while vitamin D helps the body absorb calcium and supports normal bone metabolism.

Even so, previous evidence reviews have generally found that taking calcium or vitamin D alone does not reduce fracture risk. Results have been less consistent when the two are taken together, and researchers have also remained uncertain about whether vitamin D can meaningfully reduce falls.

Despite those unanswered questions, vitamin D supplements (with or without calcium) are still commonly recommended by clinicians, guidelines, and regulatory agencies for bone health. Prescriptions have also risen substantially in recent years.

Researchers Reviewed 69 Randomized Trials

To get a clearer picture, researchers in Canada examined results from 69 randomized controlled trials involving 153,902 adults.

Randomized controlled trials are considered one of the strongest ways to test whether a treatment works because participants are assigned to different treatment groups, helping researchers reduce the influence of other factors.

The trials compared calcium supplements, vitamin D supplements, or a combination of the two with either a placebo or no treatment. Researchers focused on whether the supplements reduced fractures and falls.

The studies varied in quality, but the team assessed the risk of bias and the certainty of the evidence using established research methods.

Little Evidence of Meaningful Fracture Prevention

After setting thresholds for what would count as a clinically meaningful benefit, the researchers found little to no effect on the chance of experiencing any fracture.

For calcium supplements, that conclusion was based on moderate certainty evidence from 11 trials involving 9,067 participants.

For vitamin D supplements, the researchers found high certainty evidence from 36 trials involving 92,045 participants.

For calcium and vitamin D taken together, high certainty evidence from 15 trials involving 51,126 participants also showed little to no meaningful effect.

The same general pattern appeared when researchers looked at specific outcomes, including hip fractures and falls. Calcium, vitamin D, and combined supplementation all appeared to have little to no effect, with most of the evidence rated as moderate to high certainty.

Important Exceptions Remain

The researchers caution that some parts of the analysis were based on relatively small numbers of trials or participants, meaning those findings should be interpreted carefully.

The conclusions may also not apply to everyone. In particular, people with certain bone disorders or those receiving medication for osteoporosis may have different needs and should not assume the findings apply directly to them.

Still, the results remained broadly consistent when researchers accounted for factors including age, sex, previous fractures, previous falls, and average calcium intake from food. That consistency strengthened confidence in the overall conclusions.

Researchers Question Routine Supplementation

Based on the findings, the researchers say the evidence "does not support routine supplementation with calcium or vitamin D, or combined supplementation to prevent fractures and falls."

They also argue that clinicians, guideline panels, and regulatory agencies "should re-evaluate their general recommendations for calcium and vitamin D supplementation in light of current evidence."

Researchers writing in a linked editorial say more rigorous and well-powered trials are still needed to determine whether supplementation might benefit people at especially high risk.

Exercise May Offer More Meaningful Protection

For now, the editorial authors suggest shifting more attention and funding toward approaches that have already shown meaningful benefits for preventing falls and related injuries.

Source: ScienceDaily

Scientists discover a hidden “ID card” in cat urine

 Cats rely heavily on scent to learn about one another, often gathering information from urine and other odor marks left behind in their surroundings. These chemical traces can continue communicating long after the animal that produced them has moved on.

That creates a puzzle. Many odor molecules evaporate, break down, or change with time. If a scent is constantly evolving, how can another animal still determine who originally left it?

Researchers from Japan, Germany, and Spain, led by Iwate University, may have found part of the answer in domestic cats. Their experiments point to a group of unusual fatty acids that could serve as a lasting chemical signature in cat urine.

The scientists identified 13 branched-chain fatty acids (BFAs). The particular mixture and proportions of these compounds varied from one cat to another, yet remained relatively consistent within the same animal. Behavioral tests also showed that cats could detect differences between BFA profiles when the researchers controlled for other lipids in the urine.

The findings suggest that BFAs could function as a durable chemical "calling card" that helps preserve information about individual identity. The study will be published in Current Biology.

Cats Remember Individual Urine Scents

Before searching for the chemicals involved, the researchers first needed to establish that cats could distinguish urine from different individuals.

When cats encountered the same urine sample repeatedly, they gradually spent less time investigating it. But when urine from a different cat was introduced, their interest rose again, and they spent more time sniffing.

Remarkably, cats continued to show reduced responses to previously encountered urine odors even after gaps lasting months. That pattern suggests that cats may retain long-term memories of particular urine scents.

Researchers also examined the flehmen response, the characteristic open-mouthed expression often seen when cats investigate certain odors. Cats displayed this response more often when smelling unfamiliar urine than when smelling their own.

As the same urine was presented again and again, the flehmen response became less frequent. When urine from another cat was introduced, however, the response increased once more.

"After confirming that cats can distinguish individual urine odors, we used the flehmen response as a clue to identify urinary molecules that may contribute to individual scent recognition," said Professor Masao Miyazaki of Iwate University, who led the research project.

13 Unusual Fatty Acids Form Distinctive Profiles

Using the cats' behavior as a guide, the scientists narrowed their search to a lipid fraction in urine containing unusual BFAs.

They ultimately identified 13 of these compounds. Based on a review of existing scientific literature, the researchers found no previous reports of the same BFAs occurring in mammalian excretions or secretions.

What stood out was not simply the presence of the compounds, but the pattern they formed. Each cat had a BFA profile defined by the combination and relative abundance of the different fatty acids.

Those profiles varied considerably between animals, while remaining comparatively stable when the same cats were sampled on different dates.

Genetics also appeared to play some role. Related cats generally had more similar BFA patterns, although each animal still maintained its own distinguishable profile even within the same family.

The compounds also proved relatively durable. Many volatile chemicals responsible for urine odor begin changing quickly once urine is deposited. BFAs, by contrast, are semi-volatile and evaporate more slowly.

In urine-soaked samples stored at 25°C, the distinctive BFA profiles associated with individual cats remained comparatively stable for at least 24 hours.

Cats Can Detect the Chemical Differences

The researchers then tested whether the cats themselves could actually distinguish these BFA patterns.

They controlled the other lipid components in the urine samples and changed only the donor-derived BFA-containing fraction. Cats that had already become accustomed to the original sample began sniffing more again when the BFA fraction was switched.

That behavioral change provided evidence that cats can perceive differences among individual BFA compositions.

The result strengthens the idea that these fatty acids may carry meaningful information about identity rather than simply being unusual chemical byproducts.

Source: ScienceDaily

Extreme drought now covers 44% of Puerto Rico

 Puerto Rico typically enters its wet season in May, but 2026 has unfolded very differently. By late August, rainfall had remained scarce across much of the U.S. territory, allowing drought conditions to spread rapidly. The lack of rain has contributed to water shortages and rationing in some communities, prompting Puerto Rico's governor to declare a state of emergency in late July. In late August, the U.S. government also issued a drought disaster declaration covering more than two dozen cities and towns.

The map shows the severity and geographic extent of drought across Puerto Rico on August 25, 2026. It was created by the U.S. Drought Monitor, a collaboration involving the National Drought Mitigation Center at the University of Nebraska-Lincoln, the U.S. Department of Agriculture (USDA), the National Oceanic and Atmospheric Administration, and NASA.

NASA has supported the project for years with Earth observations and scientific expertise. That involvement expanded in 2026 when two NASA scientists joined the small group responsible for producing the weekly drought assessments.

David Mocko, a senior research scientist in the Hydrological Sciences Laboratory at NASA's Goddard Space Flight Center, said the effects of the unusually hot and dry conditions were visible across multiple types of satellite and ground-based data used by the U.S. Drought Monitor.

For recent Puerto Rico updates, particularly important information included satellite estimates of soil moisture, along with weather measurements and observations of streamflow and well conditions, Mocko said.

Mocko prepared the U.S. Drought Monitor update for August 18, 2026. He and Jonathan Case of NASA's Marshall Space Flight Center are the first NASA scientists to produce the weekly maps.

Extreme Drought Covers 44 Percent of the Territory

By August 25, 2026, about three-quarters of Puerto Rico was experiencing at least moderate drought, according to the assessment. Extreme drought zones (dark orange) in eastern and southwestern parts of the main island had expanded during the previous week and covered 44 percent of the territory.

The change happened quickly. Just three months earlier, none of Puerto Rico was classified as being in drought, and less than 20 percent of the territory was considered abnormally dry.

Late winter and early spring had actually been wetter than normal across the U.S. Caribbean, according to a National Integrated Drought Information System (NIDIS) report. Conditions then shifted sharply toward dryness.

Rainfall Falls Far Below Normal

From mid-May through mid-July, most of Puerto Rico received less than 60 percent of its normal precipitation, according to NIDIS. Southern and southwestern areas were even drier, receiving less than 20 percent of normal rainfall. That translated to a rainfall deficit of 3 to 6 inches (76 to 152 millimeters).

High temperatures made the drying worse. San Juan, for example, experienced one of its warmest Julys on record. River levels also fell sharply, with streamflow reaching record lows in waterways including the Rio Fajardo in northeastern Puerto Rico.

Water Shortages Hit Residents and Farmers

The strain on water supplies has affected residents, farmers, and ranchers across Puerto Rico. Water rationing has been in effect in several municipalities since early August, according to news reports. Observers have also pointed to infrastructure issues as a factor worsening the shortages.

The drought has also created serious challenges for agriculture. For farmers, dry soils have disrupted the growth of fruit and cacao trees as well as banana and coffee plants, contributing to crop losses. Ranchers, meanwhile, are seeing their hay supplies dwindle.

Drought Maps Help Guide Emergency Response

U.S. Drought Monitor maps have been published since 1999 and are used by federal, state, local, and tribal officials to help guide drought response decisions.

The USDA, for example, relies on the maps as part of a "fast track" process for issuing disaster designations. Those designations can help direct emergency assistance and other resources to affected communities.

Source: ScienceDaily

Indonesia’s most dangerous fires are burning underground

 Tropical peatland fires rank among the most dangerous and stubborn fires on Earth. Instead of racing through trees and vegetation, these fires smolder through dried wetland soils and large deposits of peat, often continuing underground at relatively low temperatures. That makes them extremely difficult to extinguish and exceptionally polluting.

By one estimate, peat fires produce three times more fine particulate matter than other tropical forest fires, along with five times more sulfur dioxide, three times more organic carbon, and twice as much methane and carbon monoxide.

Satellite Images Reveal Indonesia's Fire Season

Indonesia's 2026 fire season was already underway when the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard NASA's Aqua satellite captured an image of the region on September 1, 2026.

On the annotated map, each red dot represents a "fire detection." This means the satellite sensor and an algorithm identified a pixel containing thermal anomalies associated with fire. A single fire can produce multiple detections.

Peat fires are a persistent problem in Indonesia, which contains about 36 percent of the world's tropical peatlands. During severe droughts, these normally wet landscapes can dry enough to ignite. Over the past three decades, such conditions have repeatedly produced long-lasting fires that blanket large areas in smoke for weeks and disrupt the lives of millions of people.

El Niño Is Intensifying the Dry Season

Wildfires occur in Indonesia every year, but some of the most destructive seasons in recent decades came during El Niño, particularly in 1997 and 2015.

NOAA assessed El Niño as present and strengthening in August 2026. The climate pattern commonly reduces rainfall across Indonesia. The drying can become even more pronounced when El Niño occurs alongside a positive phase of the Indian Ocean Dipole, which was also underway.

"Indonesia is only about three weeks into its fire season, but we're seeing fire activity track sharply upward, similar to 2015," said Robert Field, a Columbia University researcher who developed a tool called the Global Fire Weather Database that produces experimental, real-time fire weather forecasts.

"The strong El Niño is making the dry season drier over the fire-prone parts of the country and exacerbating burning -- just as we anticipated it would," he said.

The comparison with 2015 is significant. After more than three months of burning that year, Indonesia's fires had emitted 1.75 billion tons of greenhouse gas equivalents -- more than Japan emits in an entire year. By September 2, the 2026 fires had been burning for about a month and had already released roughly 10 percent of the amount produced during the 2015 crisis.

Underground Peat Fires Can Burn for Months

Indonesia was also experiencing severe, widespread drought during the summer of 2026, much as it did in 2015. Data from the Indonesian meteorological agency showed that about 90 percent of the country received little or no rainfall in early August.

Under normal conditions, peat deposits in Kalimantan, Sumatra, and Papua are too wet for fire to move underground. Drought changes that dramatically, allowing flames to enter the peat itself and continue smoldering below the surface.

"Surface fires are less of a concern, but when fires get underground, they just won't stop," Field said. "They'll keep burning until the rains come in October or November."

Indonesia relies on observations from NASA and NOAA satellites to follow active fires in near-real-time. MODIS and VIIRS are among the main instruments used. Indonesia's Ministry of Forestry operates the SiPongi fire-monitoring platform using MODIS and VIIRS data, and the system counted 946 hotspots on August 31, 2026.

The Worst Fires Can Be Hardest to See From Space

Satellite monitoring has important limitations, however. MODIS and VIIRS can struggle to detect fires hidden by thick smoke or clouds, burning beneath the forest canopy, or smoldering underground inside peat deposits.

In fact, when Indonesian fires become especially intense, the number of fires detected by MODIS or VIIRS can sometimes decline because the smoke itself blocks the satellites' view.

"The worst smoke events, paradoxically, can be the hardest to observe from space with MODIS and VIIRS," said Mark Cochrane, an ecologist at the University of Maryland Center for Environmental Science who has conducted field research on peat fires in Indonesia for nearly a decade.

Some of Indonesia's modern fire vulnerability can be traced back decades. According to Cochrane, extensive construction of irrigation canals and drainage of peat swamps during the 1990s, undertaken in part to create massive rice farms, lowered water tables across wetland areas and made the landscape more combustible. Oil palm plantations and other plantation forestry are also widespread in the region.

Following the unusually grim fire season of 2015, governments and other organizations attempted to reverse some of that damage. Projects have included blocking irrigation canals to help restore wetlands, strengthening firefighting capabilities, and stepping up efforts to prevent accidental human ignitions.

2026 Could Be a Major Test of Fire Protections

"This year will be a real stress test of the measures that were put in place after 2015," said Shi Jun Wee, a University of Maryland graduate student.

Wee is part of a team working with NASA and MapBiomas to develop improved methods for spotting understory fires that MODIS and VIIRS may miss. Their approach uses shortwave infrared observations from Landsat and Sentinel-2 satellites.

As the 2026 fire season continues, Wee plans to follow conditions using NASA's Worldview data browser, FIRMS (Fire Information for Resource Management System), HLS (Harmonized Landsat and Sentinel-2) observations, and GFED (Global Fire Emissions Database).

Hazardous Smoke Is Already Disrupting Daily Life

For people living in Indonesia and neighboring countries, the effects are already being felt. Indonesian officials have warned that large portions of the population have been exposed to hazardous smoke.

According to news reports, some schools have begun switching to remote learning, nine national parks have closed, and several flights have been delayed because of heavy smoke.

Cochrane cautioned that attention to the problem often rises during major El Niño fire seasons and fades once conditions improve.

"People tend to focus on these fires during an El Niño and then forget about them," Cochrane said. "We need sustained focus, even during the years when they aren't as bad, to solve this," he said. "These fires create a tremendous amount of emissions."

Source: ScienceDaily

Antarctica gained a record 695 billion tons of ice. Scientists found the surprising reason

 A persistent patch of unusually warm tropical ocean helped intensify snowfall over East Antarctica, contributing to a temporary net ice sheet mass gain of about 695 billion tons, according to a new study published in Nature on August 19.

Researchers found that sustained warming in the tropical warm pool during 2021-23 set off a chain of atmospheric changes that ultimately affected weather thousands of miles away in Antarctica. The warming generated a Rossby wave train that traveled toward the continent, helped establish a north-south circulation pattern over East Antarctica, altered the movement of moisture, and increased regional snowfall. Together, these changes temporarily slowed the Antarctic Ice Sheet's overall loss of mass.

A Remarkable Antarctic Ice Gain

The Antarctic Ice Sheet is a major source of uncertainty when scientists estimate how much global sea levels could rise in the future. During the past two decades, Antarctica has lost ice at an average rate of approximately 140.5 billion tons per year.

Yet between 2021-23, that pattern briefly shifted. The ice sheet gained about 695 billion tons of mass, making it the largest Antarctic mass gain observed by the GRACE satellite missions.

To understand what caused the unusual increase, researchers led by the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) brought together several types of evidence. They analyzed gravity satellite measurements, snow accumulation records preserved in ice cores, and simulations of atmospheric circulation. Their goal was to determine where the extra moisture came from and how weather patterns delivered it to East Antarctica.

A Climate Signal From the Tropics

The team identified sustained warming in the tropical warm pool during 2021-23. This region lies where the tropical western Pacific meets the eastern Indian Ocean and contains some of the planet's warmest ocean waters.

That warming triggered what scientists call a Rossby wave train, a large-scale pattern of atmospheric waves capable of transmitting changes in weather and circulation across enormous distances. The disturbance traveled toward the high southern latitudes and helped reorganize atmospheric conditions around Antarctica.

Eddy mean flow feedbacks strengthened and prolonged the resulting circulation pattern. This produced a north-south dipole, with unusual low pressure south of Australia and unusual high pressure along the East Antarctic coast.

The resulting pressure pattern changed the routes taken by moisture moving through the atmosphere. In particular, it strengthened the transport of water vapor from the midlatitude Indian Ocean toward East Antarctica through atmospheric rivers.

Atmospheric Rivers Fueled Heavy Snowfall

Atmospheric rivers are relatively narrow corridors in the atmosphere that can carry enormous amounts of water vapor over long distances. When they reach cold regions such as Antarctica, that moisture can fall as heavy snow.

Water vapor tracking simulations showed that the dipole circulation directed moist air from the midlatitude Indian Ocean toward East Antarctica and allowed more atmospheric rivers to reach the continent. This produced sustained heavy snowfall across the Queen Mary Land-Wilkes Land region, adding substantial mass to the ice sheet.

Atmospheric circulation model experiments provided further evidence that warming of the tropical warm pool directly drove both the circulation changes and the increase in snowfall.

The researchers also examined how much of the snowfall increase could be attributed to anthropogenic forcing. They found that this contribution was equivalent to only 9% of the observed snowfall anomaly. That result suggests that the general increase in atmospheric moisture associated with global warming was not the main explanation for this particular event.

A Remote Antarctic "Regulator"

Additional observations and simulations indicate that comparable periods of sustained warming in the tropical warm pool occur approximately once every decade.

The researchers therefore describe the tropical warm pool as a remote "regulator" that can influence snowfall and ice mass in East Antarctica over periods lasting several years. Changes in tropical ocean temperatures can alter atmospheric circulation in ways that ultimately affect how much snow falls on the distant Antarctic continent.

The findings reveal a long-distance climate connection in which conditions in the tropics can have major consequences for Antarctica.

Antarctica Is Still Losing Ice Over the Long Term

Despite the striking 695-billion-ton increase, the researchers emphasize that the event was temporary and does not reverse the long-term decline of the Antarctic Ice Sheet.

The West Antarctic Ice Sheet continues to lose mass. Some outlet glaciers in East Antarctica also remain vulnerable as warm ocean water melts ice shelves from below and contributes to faster ice flow.

The study shows how sustained warming in the tropical warm pool can temporarily increase the mass of the Antarctic Ice Sheet through changes in atmospheric circulation and snowfall. It also identifies the north-south dipole circulation over East Antarctica as an important link connecting tropical climate conditions with changes in Antarctic ice mass.

"We found a previously underrecognized 'tropical warm pool-East Antarctic Ice Sheet' teleconnection pathway," said Yunhe Wang from IOCAS, first author of the study. "Our research provides a theoretical basis for understanding Antarctic ice-sheet mass changes and conducting future research on the East Antarctic climate."

Source: ScienceDaily