Evaluating Uncertainty and Modes of Variability for Antarctic Atmospheric Rivers

Area of Science:

• Atmospheric Science
• Climate Science
• Polar Meteorology

Background:

• Antarctic atmospheric rivers (ARs) significantly impact the continent and coastlines.
• Uncertainty in AR detection methods complicates the quantification of their impacts.
• Existing global detection tools often fail to capture ARs over the Antarctic ice sheet.

Purpose of the Study:

• To assess the uncertainty in Antarctic AR metrics due to detection methods.
• To evaluate the large-scale synoptic environments driving Antarctic ARs.
• To investigate the influence of climate variability modes on Antarctic ARs.

Main Methods:

• Utilized data from the Atmospheric River Tracking Method Intercomparison Project (ARTMIP).
• Employed global reanalysis datasets for atmospheric data.
• Compared Antarctic-specific AR detection tools with global detection tools.
• Analyzed AR metrics and large-scale environments in relation to decadal and interannual climate variability.

Main Results:

• Antarctic-specific AR detection tools consistently identify AR footprints inland over ice sheets.
• Global AR detection tools show limitations in capturing ARs over the Antarctic ice sheet.
• Large-scale synoptic environments associated with ARs are broadly consistent across different detection methods.
• The Antarctic western hemisphere exhibits stronger connections to decadal and interannual climate variability compared to East Antarctica.
• The Indian Ocean Dipole's influence on Antarctic ARs is amplified when in phase with the El Niño-Southern Oscillation.

Conclusions:

• Antarctica-specific detection tools are crucial for accurate AR footprint identification inland.
• Understanding regional variability is essential for improving Antarctic AR impact assessments.
• Climate variability modes like ENSO and IOD play a significant role in modulating Antarctic AR activity, particularly in the western hemisphere.