Atmospheric blocking and temperatures in the Antarctic Peninsula

Area of Science:

• Atmospheric Science
• Climate Modeling
• Antarctic Meteorology

Background:

• The Antarctic Peninsula (AP) experiences frequent blocking ridges and anticyclonic conditions, influencing extreme weather events.
• Understanding these patterns is crucial for predicting regional climate changes.

Purpose of the Study:

• To investigate historical and future atmospheric blocking patterns over the AP.
• To analyze geopotential height (Z500) and near-surface air temperature (T2m) anomalies under different climate scenarios.

Main Methods:

• Utilized ERA5 reanalysis and six Coupled Model Intercomparison Project Phase 6 (CMIP6) models for historical (1981-2010) and future (2071-2100, SSP5-8.5) periods.
• Focused analysis on 500 hPa geopotential height (Z500) and near-surface air temperature (T2m) anomalies.
• Compared model outputs with ERA5 reanalysis data.

Main Results:

• Historical analysis revealed discrepancies between CMIP6 models and ERA5, with EC-Earth3 and INM-CM4 showing closer agreement.
• Future projections indicate varied blocking trends: EC-Earth3 suggests increased blocking northwest of AP in summer and over the Bellingshausen Sea in winter.
• INM-CM4 projects minor summer Z500 height increases off AP coasts with negligible winter changes; localized intensification observed during extreme events.

Conclusions:

• Model outputs differ significantly, highlighting the need for improved blocking mechanism representation.
• Refined blocking definitions and broader model ensembles are recommended for better understanding AP climate change impacts.