Basal Melting Variability of the Ross Ice Shelf from Mixing Ratios of Simulated Water Masses (1993-2018) and Potential Climatic Drivers

Authors

• Enrico Pochini, University of Trieste
• Andrea Bergamasco, National Research Council - Institute of Polar Sciences (CNR-ISP)
• Florence Colleoni, National Institute of Oceanography and Applied Geophysics (OGS)
• Manuel Bensi, National Institute of Oceanography and Applied Geophysics (OGS)
• Giorgio Budillon, University of Naples Parthenope
• Pasquale Castagno, University of Messina
• Michael S. Dinniman, Old Dominion UniversityFollow
• Pierpaolo Falco, Marche Polytechnic University
• Emanuele Forte, University of Trieste
• Vedrana Kovačević, National Institute of Oceanography and Applied Geophysics (OGS)
• Stefanie L. Mack, University of Tokyo

Document Type

Article

Publication Date

2026

DOI

10.1029/2025JC023103

Publication Title

Journal of Geophysical Research: Oceans

Volume

131

Issue

2

Pages

e2025JC023103

Abstract

Several water masses circulate under the Ross Ice Shelf (RIS), the largest ice shelf in Antarctica, each causing basal melting with a specific spatio-temporal pattern. To investigate these patterns and their variability, we applied a mixing ratio analysis to simulated water masses from a new numerical ocean model of the Ross Sea. The simulation, which was run over 26 years (1993–2018) and which includes the RIS cavity, shows good agreement with seaborne and mooring observations. The total RIS basal melt rate is 90 Gt/yr on average, and is caused mostly by High Salinity Shelf Water (HSSW) (68%), which enters the western portion of the RIS cavity. In the eastern RIS, relatively warm modified Circumpolar Deep Water (mCDW) intrudes below a small portion of the RIS front, causing 25% of the total melting. Mainly near the Ross Island region, Antarctic Surface Water (AASW) is advected under the RIS, causing a small percentage (7%) of melting. A strong seasonal cycle is present in basal melting for all water masses. Melting by HSSW is stronger in winter, when salinification due to sea ice production is larger. By contrast, in the summer, reduced density gradients along the RIS front allow stronger intrusions of mCDW and AASW. Interannual variability is large for mCDW and AASW. Melting caused by HSSW shows decadal variability, mostly related to the salinity of HSSW, which is impacted by sea ice import from the Amundsen Sea and sea ice production in local polynyas, both potentially affected by Pacific teleconnections.

Rights

© 2026. The Authors.

This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Data Availability

The simulated output necessary to reproduce the analysis is uploaded on figshare with DOI: https://doi.org/10.6084/m9.figshare.24285976.

Original Publication Citation

Pochini, E., Bergamasco, A., Colleoni, F., Bensi, M., Budillon, G., Castagno, P., Dinniman, M. S., Falco, P., Forte, E., Kovačević, V., & Mack, S. L. (2026). Basal melting variability of the Ross Ice Shelf from mixing ratios of simulated water masses (1993–2018) and potential climatic drivers. Journal of Geophysical Research: Oceans, 131(2), e2025JC023103. https://doi.org/10.1029/2025JC023103

Repository Citation

Pochini, Enrico; Bergamasco, Andrea; Colleoni, Florence; Bensi, Manuel; Budillon, Giorgio; Castagno, Pasquale; Dinniman, Michael S.; Falco, Pierpaolo; Forte, Emanuele; Kovačević, Vedrana; and Mack, Stefanie L., "Basal Melting Variability of the Ross Ice Shelf from Mixing Ratios of Simulated Water Masses (1993-2018) and Potential Climatic Drivers" (2026). CCPO Publications. 416.
https://digitalcommons.odu.edu/ccpo_pubs/416

ORCID

0000-0001-7519-9278 (Dinniman)