Distinct Central and Eastern Pacific El Niño Influence on Antarctic Surface Mass Balance.

The El Niño‐Southern Oscillation causes anomalous atmospheric circulation, temperature and precipitation across southern polar latitudes, but the influence of Central and Eastern Pacific El Niño events on Antarctic surface mass balance and snow accumulation has not yet been assessed. Here, we use reanalysis and reanalysis‐forced regional climate model output and find that Central Pacific El Niño results in significantly increased snow accumulation in the western Ross Sea sector and significantly decreased snow accumulation in the Amundsen Sea sector. Eastern Pacific El Niño is associated with similar but weaker patterns, with some regional exceptions. In some areas, like Dronning Maud Land, or the Wilkes Subglacial Basin, the effect of El Niño on snow accumulation changes from increased to reduced accumulation depending on the type of El Niño. Our results show that projecting El Niño types is important for constraining future changes in Antarctic surface mass balance. Plain Language Summary: The El Niño‐Southern Oscillation influences the climate in Antarctica with impacts on temperature, rainfall and snow accumulation. However, the effect of two different types of El Niño events, Central Pacific and Eastern Pacific El Niño, on the patterns of snow accumulation in Antarctica has not yet been studied. We show from reanalysis and reanalysis‐forced regional climate model output that Central and Eastern Pacific El Niño events have distinct effects on Antarctic snow accumulation patterns. During Central Pacific El Niño events, there is an increase in snow accumulation in the western Ross Sea sector, and decrease in the Amundsen Sea region. Eastern Pacific El Niño events cause similar regional effects, but to a lesser extent. In some areas, like Dronning Maud Land or the Wilkes Subglacial Basin, the effect of El Niño on snow accumulation changes from increased to reduced accumulation depending on the type of El Niño. Our findings emphasize the importance of understanding projected changes in El Niño types, as these will impact the future of Antarctica's snow accumulation. Key Points: Central and Eastern Pacific El Niño events have distinctly different seasonal impacts on Antarctic surface climateCentral Pacific El Niño accumulation anomalies develop earlier than Eastern Pacific El Niño, and persist through austral winter and springCentral Pacific El Niño impacts on West Antarctic accumulation are significantly greater than those of Eastern Pacific El Niño events [ABSTRACT FROM AUTHOR]