Giant Iceberg Calves Off in Major Event in Antarctica
On May 20th, 2024, a 380 square kilometer (~147 mi²) iceberg separated from the Brunt Ice Shelf in Antarctica. This event, known as A-83, marks the third major iceberg calving in this area in the last four years.
In 2021, the first significant event occurred when A-74 separated from the ice sheet, followed by an even larger berg named A-81 in 2023.
Sentinel-1 and Landsat 8 Capture Iceberg Breakup
The breakup of this iceberg was observed by two Earth Observation satellites: ESA’s Copernicus Sentinel-1 and NASA’s Landsat 8 satellites, providing radar imaging and thermal data, respectively.
The U.S. National Ice Center officially designated the iceberg as A-83, assigning names based on the Antarctic quadrant where the iceberg was first sighted.
Because Brunt is situated in the eastern Weddell Sea, its icebergs are given an ‘A’ designation, with sequential numbers assigned to them.
Regular satellite monitoring of ice shelves enables scientists to monitor the impacts of climate change in remote regions such as Antarctica. Specifically, they can observe how ice shelves maintain their structural stability in response to changing ice dynamics and rising atmospheric and ocean temperatures.
McDonald Ice Rumples and Halloween Crack
This recent calving event, like previous ones, resulted from the weakening of the ice at the McDonald Ice Rumples and the extension of the ‘Halloween Crack‘ within the ice shelf.
The Copernicus Sentinel-1 mission employs radar imaging, providing imagery year-round regardless of daylight conditions, which is particularly crucial during the six-month Antarctic Night period when sunlight is scarce.
Missions like Landsat 8 utilize thermal imaging to assist scientists in assessing ice sheet thickness.
As depicted in the image above, thinner ice appears warmer as it closely aligns with the temperature of open water, whereas thicker continental ice appears darker.
Temperature variances between the ocean and ice sheets aid scientists in pinpointing the calving line’s location.
Iceberg Safety
Thankfully, the iceberg poses no threat to the British Antarctic Survey’s Halley VI Research Station, an international research facility monitoring Earth, atmospheric, and space weather.
Despite being on the Brunt Ice Shelf, the station relocated to the Caird coast in 2017 due to instability in the outer ice shelf.
The continuous decline of Antarctic ice stands as a clear signal of increasing global temperatures and serves as a grave alert.
In addition to raising sea levels, causing coastal flooding, and worsening extreme weather events, the reduction of polar ice leads to Earth’s oceans absorbing more solar radiation, which in turn increases temperatures.
To conclude, monitoring polar ice sheets is crucial for implementing adaptation and mitigation measures, as outlined in the IPCC’s Sixth Assessment Report (AR6).
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