Antarctica's dry interior is seeing more snow, study finds

It has been revealed that a rise in sea surface temperatures in the South Atlantic increases high-pressure blocking, and that this influence leads to increasing snowfall at Dome Fuji Station in Antarctica. A research group centered on Project Researcher Kyohei Yamada at the National Institute of Polar Research, estimated 46-year snowfall fluctuations at Dome Fuji Station in Antarctica using global reanalysis data corrected with observation data. This is expected to lead to a more accurate estimation of increases and decreases in the Antarctic ice sheet through snowfall. The study was published in the Journal of Geophysical Research: Atmospheres.

Antarctica is actually an arid region. This tendency is stronger further inland, and precipitation (snowfall) at Dome Fuji Station, located at 3,810 meters above sea level on the East Antarctic ice sheet, is only a few percent of that in Japan. This slight snowfall is divided into clear-sky precipitation (diamond dust), which continues for long durations with little precipitation per event, and extreme precipitation events, which bring large amounts of precipitation despite low frequency and short duration. Extreme precipitation events are extremely important factors involved in the mass balance of the Antarctic ice sheet and paleoclimate estimation using ice cores, but their long-term fluctuations and fluctuation mechanisms are not sufficiently understood.

Regarding snowfall data at Dome Fuji Station, a very valuable record exists from the 44th Japanese Antarctic Research Expedition. It was measured by a method in which snow in a plastic container installed on the roof of the station building was collected manually once a day for one year from February 2003 to January 2004.

The research group extracted precipitation data for a reliable period by comparing this data with visual observation records of clouds and weather by humans as well as data from a ceilometer measuring cloud and snowfall conditions. Correcting precipitation in the ERA5 global reanalysis data with this observation data, they created a highly reliable precipitation dataset and analyzed precipitation changes at Dome Fuji Station over 46 years from 1979 to 2024. They also examined the relationship between this long-term precipitation change and meteorological fields and sea surface temperatures from around the Antarctic continent to mid-latitudes.

As a result, it was revealed that snowfall at Dome Fuji Station has been increasing over the 46-year period. It was found that diamond dust did not contribute to this increase in precipitation and that the increase was due to the influence of extreme precipitation events. In addition, the intensity of individual extreme precipitation events did not change, and their frequency increased.

For extreme precipitation events to occur on the ice sheet, a large amount of water vapor must be supplied from the ocean. Dome Fuji Station is located inland at a high altitude where water vapor from the ocean is extremely difficult to reach. However, when high-pressure blocking occurs and the upper-level jet stream meanders, a large amount of water vapor flows into the inland. For it to reach Dome Fuji Station, the position of occurrence of high-pressure blocking and the resulting meandering of the jet stream become important.

Over these 46 years, it was found that the frequency of having a ridge of atmospheric pressure meandering in the 45 degrees East direction had increased. This is a direction in which water vapor easily flows into the Dronning Maud Land region, including Dome Fuji Station. Furthermore, the research group analyzed the relationship between snowfall fluctuations at Dome Fuji Station and sea surface temperature fluctuations. The analysis results revealed that the snowfall fluctuations are connected with the rise in sea surface temperatures in the South Atlantic between 40 to 50 degrees South latitude and 30 degrees West to 30 degrees East longitude between the South American continent and the South African continent.

From these results, it is thought that the rise in sea surface temperatures in the South Atlantic increased the frequency of high-pressure blocking, driving increased precipitation at Dome Fuji Station.

While the Antarctic ice sheet increases through such snowfall and decreases through melting and discharge, future predictions are important because overall increases and decreases in the ice sheet affect global sea levels. Moving forward, to predict future changes in the Antarctic ice sheet, the research group will advance research toward clarifying more specific snowfall processes explaining this correlation between sea surface temperature rise and inland Antarctic snowfall through high-pressure blocking and atmospheric rivers.

Journal Information
Publication: Journal of Geophysical Research: Atmospheres
Title: Interannual Variations of Precipitation Events at Dome Fuji Station, Antarctica
DOI: 10.1029/2025JD045296