Measurements of Iceberg Melt Rates Using High-Resolution GPS and Iceberg Surface Scans

Increasing freshwater input to the subpolar North Atlantic through iceberg melting can influence fjord-scale to basin-scale ocean circulation. However, the magnitude, timing, and distribution of this freshwater have been challenging to quantify due to minimal direct observations of subsurface iceberg geometry and melt rates. Here we present novel in situ methods capturing iceberg change at high-temporal and -spatial resolution using four high-precision GPS units deployed on two large icebergs (>500 m length). In combination with measurements of surface and subsurface geometry, we calculate iceberg melt rates between 0.10 and 0.27 m/d over the 9-day survey. These melt rates are lower than those proposed in previous studies, likely due to using individual subsurface iceberg geometries in calculations. In combining these new measurements of iceberg geometry and melt rate with the broad spatial coverage of remote sensing, we can better predict the impact of increasing freshwater injection from the Greenland Ice Sheet.

Automated summary

The study presents a novel in situ method using high-precision GPS units to capture iceberg melt rates at a high temporal and spatial resolution. The calculated melt rates are lower than previous studies, likely due to using individual subsurface iceberg geometries in calculations. By combining these new measurements with remote sensing data, a better prediction of the impact of increasing freshwater input from the Greenland Ice Sheet can be made.