Winter seal-based observations reveal glacial meltwater surfacing in the southeastern Amundsen Sea

• Published in: Communications Earth & Environment
• Main Authors: Zheng, Yixi, Heywood, Karen J., Webber, Benjamin G. M., Stevens, David P., Biddle, Louise C., Boehme, Lars, Loose, Brice
• Other Authors: China Scholarship Council, University of East Anglia, National Science Foundation, RCUK | Natural Environment Research Council
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: General Earth and Planetary Sciences; General Environmental Science; Amundsen Sea; Pine Island Glacier; Ice Sheet; Ice Shelves
• Online Access: http://dx.doi.org/10.1038/s43247-021-00111-z; http://www.nature.com/articles/s43247-021-00111-z.pdf; http://www.nature.com/articles/s43247-021-00111-z

Abstract Determining the injection of glacial meltwater into polar oceans is crucial for quantifying the climate system response to ice sheet mass loss. However, meltwater is poorly observed and its pathways poorly known, especially in winter. Here we present winter meltwater distribution near Pine Island Glacier using data collected by tagged seals, revealing a highly variable meltwater distribution with two meltwater-rich layers in the upper 250 m and at around 450 m, connected by scattered meltwater-rich columns. We show that the hydrographic signature of meltwater is clearest in winter, when its presence can be unambiguously mapped. We argue that the buoyant meltwater provides near-surface heat that helps to maintain polynyas close to ice shelves. The meltwater feedback onto polynyas and air-sea heat fluxes demonstrates that although the processes determining the distribution of meltwater are small-scale, they are important to represent in Earth system models.