Role of the South Pacific Convergence Zone in West Antarctic Decadal Climate Variability

Regional atmospheric circulation along coastal West Antarctica associated with the Amundsen Sea Low (ASL) mediates ice shelf melt that governs Antarctica's contribution to global sea level rise. In this study, the South Pacific Convergence Zone (SPCZ) is identified as a significant driver of ASL variability on decadal time scales. Using the Community Earth System Model, we impose a positive sea surface temperature anomaly in the SPCZ that reproduces an increase in convective rainfall in the southwest SPCZ that has been observed in recent decades, consistent with the negative phase of the Interdecadal Pacific Oscillation (IPO). Many of the major climate shifts across West Antarctica during the 2000-2014 period when the IPO was negative can be explained via a teleconnection over the ASL emanating from the SPCZ. Knowledge of these relationships significantly enhances our understanding and interpretation of past and future West Antarctic climate variability.