Overview of the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6)

Transcription

1 Overview of the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) S. Nowicki & ISMIP6 13th July 2017 Sophie Nowicki (USA) Tony Payne (UK) Eric Larour (USA) Ayako Abe- Ouchi (JP) Heiko Goelzer (BE & NL) Jonathan Gregory (UK) William Lipscomb (USA) Helene Seroussi (USA) Andrew 1 Shepherd (UK)

2 Ice sheets & sea level within IPCC cycle FAR SAR No major dynamic response of the ice sheets was expected during the 21 st century. Main contributor to sea level rise: thermal expansion and melting of glacier. We know everything

3 Ice sheets & sea level within IPCC cycle FAR SAR AR4 understanding of these effects (rapid dynamical changes in ice flow) is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise. IPCC, 4th Assessment Report (2007) We know nothing

4 Ice sheets & sea level within IPCC cycle FAR SAR AR4 AR5 Projection of sea level rise are larger than in the AR4, primarily because of improved modeling of land-ice contribution. IPCC, 5 th Assessment Report, 2013 We know something, but not enough

5 Ice sheets & sea level within IPCC cycle FAR SAR AR4 AR5 0 Shannon et al., 2013 Change in VAF (m sle) SeaRISE models CISM2 SICOPOLIS ISSM AIF UMISM IcIES Elmer/Ice PISM Time (years) Bindschadler et al., 2013 and what we know is based on AR4 climate scenarios...

6 Ice sheets & sea level within IPCC cycle FAR SAR AR4 AR5 AR6 What is ISMIP6? Aims to provide framework linking ice- sheet modelling to the CMIP process So that ice sheet mass budget (hence SL contribu_on) becomes part of the standard CMIP dataset Ensure process- based es_mates are available to the next IPCC assessment + =

7 Experimental framework for ISMIP6 CMIP6 AOGCMs Forcings Feedbacks Analysis of climate over and surrounding the ice sheets for selected CMIP6 experiments How do dynamic ice sheets affect climate? Coupled AOGCM- ISM Standalone ice sheets models Projec1ons Past and future sea level due to ice sheets, along with associated uncertainty due to ice sheets and climate forcing ISMIP6 is a targeted ac_vity of CliC that addresses two of the WCRP Grand Challenges: mel'ng ice and sea level

8 What will the actual ISMIP6 simulafons be? Feedbacks Coupled AOGCM- ISM Standalone ice sheets models Projec1ons - Pre- industrial control - 1% per yr CO2 to 4xCO2 - Scenario RCP8.5/SSP5x (to year 2300) ISMIP6 ISM only exp CMIP6 AOGCMs Forcings ISMIP6 AOGCM- ISM exp - ISM control - ISM for last few decades (AMIP) - ISM for the historical period - ISM forced by 1% per yr CO2 to 4xCO2 - ISM for 21st / 23rd century (RCP8.5/SSP5x) - ISM for Last Interglacial - ISM specific experiments to explore uncertainty

9 ISMIP6 had to define a protocol for CMIP6 variables related to ice sheets

10 10 Climate Modeling Centers have signed up to ISMIP6

11 20 insftufons (13 ice sheet models) have signed up to ISMIP6

12 ISMIP6 standalone ISM are focussing on initmip, see poster and talk by Heiko Goelzer tomorrow

13 Surface Mass Balance from CMIP5 AMIP ( ) SMB = pr- evspsbl- mrro RACMO2 cm/yr w.e Slide courtesy of R. Cullather

14 The climate models are improving over the polar regions: Greenland surface mass balance as simulated by the Community Earth System Model (RCP8.5, 5km resolufon) Vizcaino et al., 2014

15 CMIP ocean models struggle in the polar regions and ice- ocean coupling is extremely challenging, so obtaining oceanic forcing for ice sheet models is even more tricky Bathymetry in CMIP5 models

16 So, what can we expect from ISMIP6? Assessment of climate over and surrounding the ice sheets from climate models taking part in CMIP6 Improved projec_ons of ice sheet contribu_on to sea- level change Assessment of ice- climate feedbacks from coupled AOGCM- ISM experiments Improved interac_ons between ice sheet and climate modelling communi_es 16

17 For more informafon about ISMIP6

18 For more informafon about ISMIP6

19 For more informafon about ISMIP6

20 For more informafon about ISMIP6

21 V obs (m/yr) Melt Rate (m/yr) CMIP ocean models struggle in the polar regions and ice- ocean coupling is extremely challenging Y(km) M(m/yr) Year: yr X(km) Bathymetry in CMIP5 models

22 ConnecFon to DECK, Historical and other MIPs 1. Exis_ng CMIP experiments to be analysed in terms of ice sheets forcing 2. Standalone ice sheet experiments based on CMIP model output to obtain past and future sea level, and explore uncertainty due to ice sheets 3. Coupled AOGCM- ISM experiments to explore impacts and feedbacks due to ice sheets CMIP6 exp to be used by ISMIP6 (all AOGCM) - Pre- industrial control - AMIP Diagnos_c - 1% per yr CO 2 to 4xCO 2 - Abrupt 4xCO 2 - CMIP6 Historical Simula_on - ScenarioMIP RCP8.5/SSP5x (up to year 2300) - Last Interglacial PMIP Standalone ISMIP6 exp (ISM only) - ISM control - ISM for last few decades (AMIP) Diagnos_c - ISM for the historical period - ISM forced by 1% per yr CO 2 to 4xCO 2 - ISM for 21 st / 23 rd century (RCP8.5/SSP5x) - ISM for Last Interglacial - ISM specific experiments to explore uncertainty New proposed ISMIP6 exp (coupled AOGCM- ISM) - Pre- industrial control - 1% per yr CO 2 to 4xCO 2 - Scenario RCP8.5/SSP5x (to year 2300) Tier 1 Tier 2