DOI: 10.5281/zenodo.5120376
title: Ensemble of ice shelf basal melt rates and ocean properties for tipped-over continental shelves

description: <strong>Summary</strong><strong>:</strong> This dataset contains the reference and tipped states from several model configurations developed at the Alfred Wegener Institute (AWI) and the Institut des Géosciences de l’Environnement (IGE). They were gathered here in the context of the TiPACCs European project and constitute a useful ensemble of reference and tipped ocean–ice-shelf simulations that <strong>can be used to feed ice-sheet simulations or to train melt parameterizations</strong>. The simulations produced by AWI are based on the FESOM global ocean–sea-ice model using either Z- or Sigma- coordinates and all show a cold-to-warm tipping point for Filchner-Ronne Ice Shelf. The two sets of simulations produced by IGE are based on the NEMO ocean–sea-ice model. They include a global configuration showing a cold-to-warm tipping point for Ross Ice Shelf, and regional Amundsen Sea configuration showing a warm-to-warmer transition (likely not a proper tipping point). The files include 3-dimensional and sea-floor ocean temperatures and salinities, ice-shelf melt rates, as well as topographic and grid data. All variables are interpolated onto the common 8km stereographic grid that was used to provide ocean forcing in ISMIP6 (Nowicki et al. 2020). We provide the reference state and the anomaly, so that the tipped state is: <em>Tipped = Reference + Anomaly</em> To have an overview of the reference and tipped states, have a look at these figures: <em>figure_ref_and_anomalies_1.pdf</em> <em>figure_ref_and_anomalies_2.pdf</em> <em>figure_seafloor_temp_zooms.pdf</em> _______________________________________________ <strong>Detailed Data Description</strong><strong>:</strong> <strong>reference_high_FESOM_sigma_AWI_TiPACCs.nc</strong> contact: Ralph Timmermann ralph.timmermann@awi.de, Verena Haid verena.haid@awi.de model: FESOM1.4, sigma-coordinates (global with refined grid around Antarctica) atmospheric forcing: HadCM3 20C provided average: 1990-1999 (10-year mean) more: Timmermann and Hellmer (2013) <strong>reference_low_FESOM_sigma_AWI_TiPACCs.nc</strong> contact: Ralph Timmermann ralph.timmermann@awi.de, Verena Haid verena.haid@awi.de model: FESOM1.4, sigma-coordinates (global with refined grid around Antarctica) atmospheric forcing: HadCM3 20C provided average: 1990-1999 (10-year mean) more: Timmermann and Goeller (2017) <strong>reference_FESOM_z_AWI_TiPACCs.nc</strong> contact: Verena Haid verena.haid@awi.de model: FESOM1.4, Z-coordinates (global with refined grid around Antarctica) atmospheric forcing: ERA Interim provided average: 2008-2017 (10-year mean), i.e. model year 30-39 more: same mesh as Gürses et al. (2019) <strong>reference_NEMO4_eORCA025.L121_IGE_TiPACCs.nc</strong> contact: Pierre Mathiot pierre.mathiot@univ-grenoble-alpes.fr model: NEMO-4.0, eORCA025.L121 (Global, 1/4°, 121 vertical levels) atmospheric forcing: JRA55do provided average: 2<sup>nd</sup> cycle of 1989-1998 (10-year mean); we first run 1979-2018, and we redo 1979-1998 starting from the 2018 state. more: https://pmathiot.github.io/NEMOCFG/docs/build/html/simu_eORCA025_OPM021.html <strong>reference_NEMO3_AMUXL12.L75_IGE_TiPACCs.nc</strong> contact: Nicolas Jourdain nicolas.jourdain@univ-grenoble-alpes.fr model: NEMO-3.6, AMUXL12.L75 (Amundsen, 1/12°, 75 vertical levels) atmospheric forcing: MAR (Donat-Magnin et al. 2020) provided average: 1989-2009 (21-year mean) more: similar model set-up as Jourdain et al. (2019). <strong>anomaly_high_FESOM_sigma_AWI_TiPACCs.nc</strong> continuation of reference_high_FESOM_sigma_AWI_TiPACCs.nc forced with HadCM3 A1B provided average: 2190-2199 (10-year mean) <strong>anomaly_low_FESOM_sigma_AWI_TiPACCs.nc</strong> continuation of reference_low_FESOM_sigma_AWI_TiPACCs.nc forced with HadCM3 A1B provided average: 2190-2199 (10-year mean) <strong>anomaly_high_FESOM_z_AWI_TiPACCs.nc</strong> same model set-up as reference_FESOM_z_AWI_TiPACCs.nc atmospheric forcing south of 60°S HadCM3 A1B starting 2050, otherwise ERA Interim starting 1979 provided average: model year 69-78 (10-year mean), i.e. 2008-2017 of 2<sup>nd</sup> 39yr-cycle <strong>anomaly_medium_FESOM_z_AWI_TiPACCs.nc</strong> same model set-up as reference_FESOM_z_AWI_TiPACCs.nc atmospheric forcing: ERA Interim modified with a strong imprint of the seasonal cycle of HadCM3 A1B 2070-2089 provided average: model year 69-78 (10-year mean), i.e. 2008-2017 of 2<sup>nd</sup> 39yr-cycle <strong>anomaly_low_FESOM_z_AWI_TiPACCs.nc</strong> same model set-up as reference_FESOM_z_AWI_TiPACCs.nc atmospheric forcing: manipulated ERA Interim with prolongued summer and shorter, milder winter south of 50°S, additional modification of winds in Weddell Sea region provided average: model year 108-117 (10-year mean), i.e. 2008-2017 of 3<sup>rd</sup> 39yr-cycle <strong>anomaly_NEMO4_eORCA025.L121_IGE_TiPACCs.nc</strong> similar to reference_NEMO4_eORCA025.L121_IGE_TiPACCs.nc perturbation of the model parameters: Different iceberg distribution and different sea-ice–ocean drag and snow conductivity on sea-ice, leading to less sea-ice production in the eastern Ross Sea. More: https://pmathiot.github.io/NEMOCFG/docs/build/html/simu_eORCA025_OPM020.html <strong>anomaly_NEMO3_AMUXL12.L75_IGE_TiPACCs.nc</strong> similar to reference_NEMO3_AMUXL12.L75_IGE_TiPACCs.nc perturbation of atmospheric forcing: MAR forced by the CMIP5 multi-model anomaly under the RCP8.5 scenario (Donat-Magnin et al. 2021). provided average: 2080-2100 (21-year average)