Multi‐Decadal Record of Sensible‐Heat Polynya Variability From Satellite Optical and Thermal Imagery at Pine Island Glacier, West Antarctica

• Published in: Geophysical Research Letters
• Main Authors: Elena Savidge, Tasha Snow, Matthew R. Siegfried
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: Geophysics. Cosmic physics; QC801-809; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Pine Island; Pine Island Glacier; Sea ice; West Antarctica
• Online Access: https://doi.org/10.1029/2023GL106178; https://doaj.org/article/c253500752b94cef931a63bea249432d

Abstract Open ocean areas surrounded by sea ice and maintained by ocean heat, or sensible‐heat polynyas, are linked to key ice‐sheet processes, such as ice‐shelf basal melt and ice‐shelf fracture, when they occur near ice‐shelf fronts. However, the lack of detailed multi‐year records of polynya variability prevent assessing coupling between polynya and frontal dynamics. Here, we present the first multi‐decadal polynya area record (2000–2022) at Pine Island Glacier (PIG), West Antarctica, from thermal and optical satellite imagery. We found substantial interannual variability in polynya area, with consistencies in the timing of polynya opening, maximal extent, and closing. Furthermore, the largest polynya in our record (269 km2) occurred at PIG's western margin just 68 days before iceberg B‐27 calved, suggesting that polynya size and position may influence rifting dynamics. Our new data set provides a pathway to assess coevolving polynya and frontal dynamics, demonstrating the importance of building long‐term, year‐round polynya variability records.