Synthetic aperture radar backscatter is influenced by bubbles at the ice/water interface of an Antarctic lake

• Published in: Communications Earth & Environment
• Main Authors: Adam Gaudreau, Denis Lacelle, Dale T. Andersen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2024
• Subjects: Geology; QE1-996.5; Environmental sciences; GE1-350; Antarc*; Antarctic; Antarctica; East Antarctica
• Online Access: https://doi.org/10.1038/s43247-024-01370-2; https://doaj.org/article/9a7163cc0daa41e7a3e1709f697188d7

Abstract Synthetic aperture radar is an invaluable tool for monitoring lake ice. This study utilizes synthetic aperture radar to analyze the 2019-2023 backscatter time series of perennially ice-covered Lake Untersee in East Antarctica. We observed stark seasonal backscatter variations, averaging –9.6 dB from December to March and –3.7 dB from May to November. These fluctuations correspond to the abundance of sub-centimeter bubbles at the ice/water interface. Notably, the backscatter increase in April-May aligns closely with variations in ice thickness across the lake. Our findings suggest that ice cover thickness influences the timing and duration of ice accretion at the bottom, the accumulation of dissolved gases and bubbles, and the resultant changes in surface roughness at the ice/water interface. These factors collectively impact the backscatter response. This study enhances our understanding of the interactions between subsurface processes and synthetic aperture radar backscatter, shedding light on the seasonal dynamics of perennially ice-covered lakes.