The regional scale surface mass balance of Pine Island Glacier, West Antarctica over the period 2005–2014, derived from airborne radar soundings and neutron probe measurements

• Main Authors: Kowalewski, Stefan, Helm, Veit, Morris, Elizabeth, Eisen, Olaf
• Format: Text
• Language: English
• Published: 2020
• Subjects: Pine Island Glacier; West Antarctica; Antarc*; Antarctica; Pine Island
• Online Access: https://doi.org/10.5194/tc-2020-102; https://tc.copernicus.org/preprints/tc-2020-102/

We derive recent surface mass balance (SMB) estimates from airborne radar observations along the iSTAR traverse (2013, 2014) at Pine Island Glacier (PIG), West Antarctica. Ground based neutron probe measurements of snow density at 22 locations allow us to derive SMB from the annual internal radar reflection layers. The 2005 layer was traced for a total distance of 2367 km allowing us to determine annual mean SMB for the period 2005–2014. Using complementary SMB estimates from the RACMO2.3p2 regional climate model and a geostatistical kriging scheme we determine a regional scale SMB distribution with the same main characteristics as that determined for the period 1985–2009 in previous studies. Local departures exist for the northern PIG slopes, where the orographic precipitation shadow effect appears to be more pronounced in our observations, and the southward interior, where the SMB gradient is more pronounced in previous studies. For the PIG basin, we derive a total mass input of 79.9 ± 19.2 Gt yr −1 . This is not significantly different to the value of 78.3 ± 6.8 Gt yr −1 for the period 1985–2009. Thus there is no evidence of a secular trend in mass input to the PIG basin. We note, however, that our estimated uncertainty is more than twice the uncertainty for the 1985–2009 estimates. Our error analysis indicates that uncertainty estimates on total mass input are highly sensitive to the selected krige methodology and assumptions made on the interpolation error, which we identify as the main cause for the increased uncertainty range compared to the 1985–2009 estimates.