Impact of radiation penetration on Antarctic surface melt and subsurface snow temperatures in RACMO2.3p3

• Main Authors: Dalum, Christiaan Timo, Berg, Willem Jan, Broeke, Michiel Roland
• Format: Text
• Language: English
• Published: 2021
• Subjects: Antarctic; The Antarctic; Antarc*; Ice Sheet
• Online Access: https://doi.org/10.5194/tc-2021-298; https://tc.copernicus.org/preprints/tc-2021-298/

This study investigates the sensitivity of modeled surface melt and subsurface heating on the Antarctic ice sheet to a new spectral snow albedo and radiative transfer scheme in the Regional Atmospheric Climate Model (RACMO2), version 2.3p3 (Rp3). We tune Rp3 to observations by performing several sensitivity experiments and assess the impact on temperature and melt by changing one parameter at a time. When fully tuned, Rp3 compares well with in situ and remote sensing observations of surface mass and energy balance, melt, temperature, albedo and snow grain specific surface area. Furthermore, the introduction of subsurface heating in Rp3 significantly improves the snow temperature profile. Near surface snow temperature is especially sensitive to the prescribed fresh snow specific surface area and fresh dry snow metamorphism. These processes, together with the refreezing grain size and subsurface heating, are important for melt around the margins of the Antarctic ice sheet. Moreover, small changes in the albedo and the aforementioned processes can lead to an order of magnitude overestimation of melt, locally leading to runoff and a reduced surface mass balance.