Melt rates in the kilometer-size grounding zone of Petermann Glacier, Greenland before and during a retreat

Warming of the ocean waters surrounding Greenland plays a major role in driving glacier retreat and the contribution of glaciers to sea level rise. The melt rate at the junction of the ocean with grounded ice—or grounding line—is, however, not well known. Here, we employ a time series of satellite radar interferometry data from the German TanDEM-X mission, the Italian COSMO-SkyMed constellation, and the Finnish ICEYE constellation to document the grounding line migration and basal melt rates of Petermann Glacier, a major marine-based glacier of Northwest Greenland. We find that the grounding line migrates at tidal frequencies over a kilometer-wide (2 to 6 km) grounding zone, which is one order of magnitude larger than expected for grounding lines on a rigid bed. The highest ice shelf melt rates are recorded within the grounding zone with values from 60 ± 13 to 80 ± 15 m/y along laterally confined channels. As the grounding line retreated by 3.8 km in 2016 to 2022, it carved a cavity abo..., , This dataset supplements the manuscript \"Melt rates in the kilometer-size grounding zone of Petermann Glacier, Greenland before and during a retreat.\" by Ciracì, E., Rignot, E., Scheuchl, B., Tolpekin, V., Wollersheim, M., An, L., Milillo, P., Bueso-Bello, J. L., Rizzoli, P., Dini, L., 2023 - in press in The Proceedings of the National Academy of Sciences (PNAS)., , # Melt rates in the kilometer-size grounding zone of Petermann Glacier, Greenland before and during a retreat

Fields 1-6 unchanged with regards to April 2022 Version. 

Added the following fields:

7\. P1M1_Bed1_Shade.tif: Shaded relief bathymetry derived from GBMF gravity data. Coordinate Reference System: EPSG:4326. Resolution: 500 m. Data format: GeoTIFF. Data type: Byte.

8\. P1M1_Bed1.tif: Bathymetry (bed elevation in meters above mean sea level) derived from GBMF gravity data acquired in 2020. Coordinate Reference System: EPSG:4326. Resolution: 500 m. Data format: GeoTIFF. Data type: Float32.

## Ciraci\_Rignot\_et\_al\_2022\_README.md - Original Version April 2023

### Repository Content:

1\. tandem-x_dem_calibrated_wrt_amsl_EPSG-3413_res-150.zip:

2011-06-09_tdemx_mosaic.tiff: TanDEM-X Digital Elevation Model organized by year (2011), month (06), day(09). Time period 2011-06-09 to 2021-12-01.Elevation is in meters above mean seal level. Coordinate Reference System: EPSG:3413. ...