Previous studies suggest that El Niño–Southern Oscillation (ENSO) variability has decreased in a warming climate and polar sea ice behaviors have impacts on it. However, due to the inseparable roles of Arctic and Antarctic sea ice melt, understanding of polar sea ice melt impacting on ENSO is limited. Here, we design a series of fully coupled simulations using the Community Earth System Model to investigate the effects of Arctic and Antarctic sea ice melt on ENSO. In such simulations, the albedo of sea ice is reduced that the increased absorption of solar radiation would melt the sea ice as in a warming climate scenario. Then, the role of the Arctic and Antarctic sea ice melt on ENSO can be detected by controlling the albedo coefficient in the Arctic and Antarctic regions separately. We find that while the sea ice melt over the Antarctic has a strong impact on ENSO similar as the combined sea ice melt in both polar regions, variability of the ENSO exhibits a relatively weak sensitivity to the Arctic sea ice melt. Physical diagnotics show that the response of ENSO to sea ice melt is characterized by weakened sea level pressure (SLP) anomalies in the eastern Pacific Ocean and enhanced SLP anomalies in the central Pacific Ocean. As a result, weakened the walker circulation in the sea ice melt experiments and reduced ENSO variability. Thus, this study identifies a reduce ENSO variability in response to sea ice melting, providing key insights into the relationship between ENSO and tropical Pacific climate variability.
 

ENSO,Sea Ice Melting,Global Warming,Walker Circulation,Kelvin Waves,Upwelling