Testing a PICO quadratic sub-shelf basal melt module in the GRISLI ice sheet model

The Antarctic ice sheet dynamics is primarily driven by basal melting under the ice shelves. The limitation of computational resources forces the usage of simplified parametrizations in ice-sheet models. Multiple parametrizations have been developed and implemented over the last years (Reese et al. 2018, Lazeroms et al. 2018, Pelle et al. 2019, Jourdain et al. 2020, etc.). The PICO module (Reese et al. 2018) demonstrates to be a good trade-off between complexity and computational resources for paleo ice-sheet reconstructions. Lately, Burgard et al. 2022 suggested that the implementation of a quadratic version of the PICO module could improve it significantly.

Here we test the implementation of the PICO module with a quadratic relationship between the thermal forcing and the melt in the GRISLI ice sheet model. We test a wide range of parameter values to calibrate the module, we compare the quadratic version of the module with the original version, under 2 different resolutions. Eventually, we show the results of simulations on paleo and future applications.