Observations of ice-stream velocity variability associated with subglacial lake activity in Antarctica

Active subglacial lakes beneath the Antarctic Ice Sheet undergo repeated filling and drainage cycles that are now routinely identified using satellite altimetry. Recent studies have shown that such lakes are widespread and dynamically active, with more than few dozen active systems detected across Antarctica (Wilson et al., 2025). Even though these lakes are expected to influence basal water pressure, their impact on surface ice-stream velocity are inadequately constrained by observations.
In this study, we examine whether subglacial lake fill and drain events cause measurable, time-lagged changes in ice-stream surface velocity. The analysis focuses on a few well-documented active subglacial lakes located near major ice streams. Surface elevation time series from CryoSat-2 are used to identify lake filling and drainage phases and to quantify the timing and magnitude of individual events, also with ICESat-2 data used for validation where available. Ice velocity time series derived from Sentinel-1 are extracted at multiple locations upstream and downstream of each lake and are detrended to isolate velocity anomalies.
We analyse the relationship between lake elevation changes and velocity anomalies using correlation and lead lag methods, and assess how any velocity response varies with distance from the lake. Statistical significance is evaluated relative to background velocity variability and sensitivity to spatial averaging. The results provide observational constraints on the coupling between subglacial hydrology and ice dynamics, and help to assess whether subglacial lake activity can produce detectable surface velocity responses at satellite resolution.

 

Wilson, S.F., Hogg, A.E., Rigby, R. et al. Detection of 85 new active subglacial lakes in Antarctica from a decade of CryoSat-2 data. Nat Commun 16, 8311 (2025). https://doi.org/10.1038/s41467-025-63773-9