Evolution of snow and firn on the Juneau Icefield, Alaska (2024)

Alpine glaciers of Alaska are a significant contributor to global sea-level rise. Most Alaskan glaciers lose mass through surface melting due to increasing atmospheric temperatures, which may change regional glacier hydrology, including firn properties and the firn's meltwater retention and runoff. We use field observations and firn modeling to investigate seasonal to decadal changes in the thermal and physical properties of firn on the Juneau Icefield, Alaska, and the impacts on the firn column’s capacity for refreezing meltwater. Our results reveal local and transient retention of liquid water in the snow and firn during the 2024 melt season. We also find that the long-term firn column’s capacity to refreeze liquid water (rain/melt) is decreasing due to decreasing firn cold content.
The first dataset contains measurements collected during June and July of the 2024 field season at four sites on the Juneau Icefield (MLD, MG3, NWB1, and TKG4). These include density, permittivity, liquid-water content, and ablation rates. The documents "Juneau_Icefield_Firn_Core_Data_2024.csv" and "Juneau_Icefield_Ablation_Data_2024.csv" contain these data for all sites. The second dataset contains modeled results from using the Community Firn Model and the climate forcing used to run the model, including firn density, temperature, thickness, refreeze, and runoff, atmospheric temperature, snow accumulation, melt, and rainfall. The documents "mg3_model_results.csv," "mld_model_results.csv" and "nwb1_model_results" contain these data for the three sites in the accumulation zone (MLD, MG3, NWB1).