Taku Glacier, Alaska Global Navigation Satellite System (GNSS) Data, 2025

[Note that data has been uploaded to the ADC ftp site.]
Tidewater glaciers are known to undergo cycles of slow, centennial-scale advance and rapid, decadal-scale retreat that are driven by processes occurring at the glacier-ocean interface, including iceberg calving, submarine melting, and sediment deposition and erosion. These cycles can occur in a steady climate, but climate can modify the timescales of advance and retreat as well as act as a trigger. Since the advance phase is longer than the retreat phase, in a steady climate one would expect the majority of tidewater glaciers to be advancing. This is not the case at present, as the majority of tidewater glaciers around the world are retreating or in a quasi-stable configuration. Until recently, Taku Glacier in Southeast Alaska was one of the rare advancing tidewater glaciers. Recent observations indicate that, due to a warming climate, the glacier is now thinning over its entire area and has begun to retreat off of the terminal moraine that it developed and prograded over the past 125 years. This project is investigating the processes by which a tidewater glacier transitions into retreat, and the evolving glacier sensitivity to climate during this transition, by analyzing drone and remote sensing observations of Taku Glacier. Satellite-derived velocity fields of the glacier unexpectedly revealed asynchronous seasonal velocity variations across the glacier; to further investigate to Global Navigation Satellite System (GNSS) receivers were deployed on the glacier during summer 2025. This data set consists of the GNSS rinex files.