24th Pacific Science Congress (PSC-24)

Some research have examined the effects of two-year La Niña events, but impacts of triple-year La Niña events and their differences relative to one or two-year La Nina events remain poorly understood. Based on long-term simulation from the pre-industrial control experiment (piControl) of the CESM2 model, we analyze associations of La Niña events with different durations (single-year, two-year, and triple-year) with Antarctic sea ice cover and discuss possible underlying physical mechanisms. We focus on the peak phase (December to February, DJF) and the lag phase (March to May, MAM) of La Niña events, and employ composite analysis to reveal the evolution of Antarctic sea ice anomaly and its relationship with atmospheric circulation, thermodynamic processes, and sea ice budget. We further analyze impacts of La Niña events after removing the effects of negative Indian Ocean Dipole (nIOD) events.
 

Multi-year La Niña; Antarctic sea ice; Sea ice budget; Rossby wave train; Indian Ocean Dipole