ENSO Modulates Summer and Autumn Sea Ice Variability Around Dronning Maud Land, Antarctica

Antarctica's sea ice cover is an important component of the global climate system, yet the drivers of sea ice variability are not well understood. Here we investigated the effects of climate variability on sea ice concentration (SIC) around East Antarctica by correlating the 40-years (1979-2018) satellite sea ice record and ERA5 reanalysis data. We found that summer and autumn SIC around Dronning Maud Land (DML) between 10 and 70 degrees E exhibited a statistically significant negative correlation with the Nino 3.4 index. Sea ice in DML was also correlated with sea surface temperature (SST) anomalies in the tropical Pacific, and to an atmospheric wave train pattern extending from the South Pacific to DML. We suggest that a southward-propagating atmospheric wave train triggered by SST anomalies in the tropical Pacific extends into DML and alters sea ice concentration by encouraging meridional airflow. Our results showed that shifts in meridional flow in DML affected sea ice thermodynamically, by altering local heat transport and in turn altering sea ice formation and melt.

Automated summary

Research found that sea ice concentration in East Antarctica is negatively correlated with the Nino 3.4 index, and is also influenced by sea surface temperature anomalies in the tropical Pacific and an atmospheric wave train pattern extending from the South Pacific to DML. The study suggests that an atmospheric wave train triggered by SST anomalies in the tropical Pacific propagates southward into DML, altering sea ice concentration by encouraging meridional airflow.