Change and variability in Antarctic coastal exposure, 1979-2020.

Area of Science:

• * Climate Science
• * Oceanography
• * Glaciology

Background:

• * Loss of sea-ice buffers in Antarctica increases coastal exposure to ocean waves.
• * This has significant implications for ice-shelf stability, coastal erosion, and marine ecosystems.
• * Understanding these changes is crucial for predicting future Antarctic environmental shifts.

Purpose of the Study:

• * To introduce and define a new climate and environmental metric: Coastal Exposure Length.
• * To quantify the daily, regional, and annual variability of Antarctic coastlines lacking sea-ice protection.
• * To analyze trends in coastal exposure from 1979 to 2020.

Main Methods:

• * Utilized a long-term satellite sea-ice concentration record (1979-2020).
• * Developed a daily metric measuring the length and incidence of Antarctic coastline without offshore sea ice.
• * Analyzed regional and circumpolar trends in coastal exposure.

Main Results:

• * Approximately 50% of Antarctica's coastline experienced no sea ice offshore during summer between 1979-2020.
• * Regional summer exposure varied, with the Amundsen-Bellingshausen seas at 45% and the Indian Ocean/Ross Sea at 58%.
• * The annual maximum length of Antarctic coastal exposure showed a slight decrease of ~0.32% per year.

Conclusions:

• * Coastal Exposure Length is a valuable metric for monitoring Antarctic environmental changes.
• * Significant portions of the Antarctic coastline are vulnerable to increased wave action and ocean influence.
• * Continued monitoring is essential to understand the long-term impacts on ice-shelf stability and ecosystems.