Researchers Have Been Studying Antarctic Fast Ice For Decades, And Here’s What They’ve Learned
“Fast ice,” also known as land-fast ice, is sea ice that remains attached to the coastline for at least 15 days, and in Antarctica, it plays a vital role.
This type of ice shields the continent’s ice from ocean waves. In the process, distinct ecological habitats for species ranging from penguins to zooplankton are formed, creating a key platform for scientific research.
However, measuring the conditions that create thick and sturdy fast ice has traditionally been a challenge. While satellites are excellent for analyzing other features of sea ice in Antarctica, including its coverage, they are less effective at determining fast ice thickness.
A recent study has provided a decades-long historical record of fast ice thickness in McMurdo Sound, which is located off the coast of Antarctica.
The records span from 1986 to 2022, and the researchers explored environmental variables linked to variations in fast ice thickness.
The findings could help scientists determine when fast ice is safe to cross and provide insights into how climate change might impact the ecosystems that rely on fast ice.
“Each winter, the ocean in McMurdo Sound freezes to form sea ice. We present land-fast sea-ice thickness measurements taken between 1986 and 2022, which we connect to properties of the atmosphere and the ocean,” the study’s authors wrote.
“This provides a baseline of the variation in land-fast sea-ice thickness between years.”
A range of data was used for this study, including manual measurements taken through drill holds and coinciding records of internal ice and ocean temperatures.
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This allowed the research team to measure fast ice thickness and estimate the ocean heat flux impacting the ice from beneath.
The results revealed that the thickness of fast ice in McMurdo Sound remained exceptionally stable over nearly four decades. Throughout the 37 years studied, there was no clear trend toward thinner or thicker ice.
It was learned that, on an annual basis, the thickness of the ice varied by as much as 0.7 meters. The previous finding that different climate factors affect fast ice formation over different timeframes was also confirmed.
More specifically, the global climate impacts fast ice formation on a decadal scale; meanwhile, short-term weather changes, like seasonal fluctuations, impact yearly variations.
Finally, the researchers identified three key factors that contributed to thicker fast ice. These included winds from the south, lower air temperatures, and reduced storminess, or measure of pressure and temperature, in the winter.
The thickest fast ice followed extended periods of cold weather, with little storm activity and winds coming from the south.
“There remains a need for a future event-based analysis, especially around extreme storm events driving winter land-fast sea-ice break up and persistence,” the study’s authors concluded.
“The present study provides a baseline against which these extreme events and long-term trends can be assessed.”
To read the study’s complete findings, which have since been published in the Journal of Geophysical Research, visit the link here.
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