Distinct El Niño Flavors and SAM Variability Modulate Surface Melt Over the Ross Ice Shelf
Year: 2026
Type: article
Abstract: Our study investigates how different flavors of El Niño, centered on the Eastern Pacific (EP) and Central Pacific (CP), and their interaction with the Southern Annular Mode (SAM) modulate surface melt events over the Ross Ice Shelf (RIS). Using satellite‐based melt observations, ERA5 reanalysis, high‐resolution regional model simulations, and CMIP6 model outputs, we assess atmospheric circulation patterns during nine El Niño events from 1979 to 2022. Results indicate that EP El Niño events, particularly when accompanied by a negative SAM phase, are more likely to be associated with pronounced mid‐tropospheric high‐pressure anomalies and warm northerly winds, which enhance longwave cloud forcing and increase the potential for widespread melt. In contrast, CP events generate weaker teleconnections with less melt. The 1997 and 1986 EP events, despite their intensity, did not produce substantial melt primarily due to the unfavorable positive SAM which weakened the effects of EP El Niño teleconnection. Model simulations confirm that EP events under pre‐industrial conditions reproduce PSA‐like wave trains conducive to RIS warming, while CP events show weaker response in the RIS region. This study highlights that the interplay between El Niño flavor and SAM critically influences surface melt across RIS, underscoring the need to improve understanding of these coupled modes to better constrain the projections of surface melt and ice shelf stability.
DOI: 10.1029/2025jd045932
Authors: Sanjiban Dutta, Pranab Deb, Ruth Mottram, Nicolaj Hansen
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,070
OpenAlex ID: W7168473189