Polar-CORDEX (Coordinated Regional Downscaling Experiment - Arctic and Antarctic Domains) is part of the international CORDEX initiative.
CORDEX is a WCRP-sponsored program to organize an international coordinated framework to produce an improved generation of regional climate change projections for input into impact and adaptation studies. The Polar CORDEX activities are coordinated through CliC.
Currently, the core of Polar-CORDEX consists of regional climate model simulations over the Arctic, with hindcast (ERA-Interim and GCM-driven historical simulations) and scenario (GCM-driven rcp4.5, rcp8.5 simulations) simulations are conducted. For an overview of Arctic CORDEX activities go to: activities/targeted/polar-cordex/arctic. This effort is now expanding to include the Antarctic region as well. For an overview of Antarctic CORDEX activities go to: http://www.climate-cryosphere.org/activities/targeted/polar-cordex/antarctic.
Focus was on atmosphere-only simulations over the Arctic CORDEX domain at ca. 50 km resolution forced by the ERA-Interim (global atmospheric reanalysis from 1979, continuously updated in real time) data. Simulations from 7 Regional Climate Models (RCMs) from different groups (Rossby Centre regional Atmospheric model (RCA4) from the Swedish Meteorological and Hydrological Institute (SMHI), Norrköping; Canadian Regional Climate Model (CanRCM4) from the Canadian Centre for Climate Modelling and Analysis (CCCma), Victoria, Canada; modelCCLMfrom Univ. of Trier, Germany, model HIRHAM5 (regional climate model)from AWI, Potsdam, Germany; model WRF from Iowa State Univ., USA; model HIRHAM5 from DMI, Copenhagen, Denmark; model RRCM from MGO, St. Petersburg, Russia) have been finished. Other RCM simulations are running (model MAR from Univ. of Liège, Belgium; model Weather Research and Forecast (WRF) from Uni Research Climate Bergen, Norway; new WRF simulations from Iowa State Univ. and Univ. of Colorado, USA). First results of individual models are published. They discussed the effects of spectral nudging on the simulations (Berg et al., 2013; Glisan et al., 2014) and established the credibility of daily precipitation extremes over four North American regions (Glisan and Gutowski, 2013) in individual models. First results of a multi-model intercomparison with respect to temperature extremes quantified the considerable regional-scale across-model scatter (Matthes et al., 2014). First scenario simulations (CMIP5 GCM-driven RCP4.5, RCP8.5 simulations) have been conducted by 3 atmospheric RCMs and the other models will start their simulations in 2015. Also, the first Arctic CORDEX simulations with a coupled atmosphere-ice-ocean RCM (RCAO from SMHI) have been conducted, both driven by ERA-Interim and GCMs. A few Antarctic CORDEX (hindcast, historical, scenario) simulations have been finished by 2 groups (model RACMO from KNMI, Netherlands; model WRF from New Mexico Inst., Socorro, USA).
The second Polar CORDEX meeting was held as a side event during the Regional-Scale Climate Modelling Workshop on 21st Century Challenges in Regional Climate Modelling in Lund, Sweden in June 2014. The status of and future plans for simulations and analysis have been discussed. Further, a link to the Arctic Council “Adaptation Actions in a Changing Arctic” (AACA) project has been established. The AACA project looks at future climate impacts, their interactions with other non-climate and socio-economic drivers of change, and the relevance of this for designing adaptation policies. It was discussed that available and relevant Arctic CORDEX results should feed into the AACA report.
The Era-Interim driven runs will be finished in 2015. All groups will put their data on the Earth System Grid Federation (ESGF) archive such that the results are readily available for scientific analysis. Multi-model analysis will then be started. One focus of this analysis will be on extreme events and cyclones. Additional analysis may focus on other mesoscale processes (e.g. atmospheric boundary layer and marginal ice zone processes, clouds, etc.), which are one aspect of the simulations expected to demonstrate added value by the RCM simulations. It would also be interesting to investigate the atmospheric response to sea ice anomalies in the RCMs. Analysis relevant for the AACA report will be conducted. Some higher resolution (ca. 25 km) circum-Arctic atmospheric simulations and very high-resolution (few km) runs for subdomains (e.g., Svalbard, Greenland) have already been done by individual groups; these will be included in these analyses.
The Polar CORDEX group also plans to downscale additional CMIP5 GCMs future projections for the Arctic CORDEX domain. In doing this we aim to arrive at a good RCM-GCM matrix, i.e. the groups will try to run their RCM with at least two different GCM forcings. Focus will be on RCM simulations for the RCP8.5 scenario. We expect to have simulations from ca. 6 RCMs.
Another goal is to set up coordinated coupled atmosphere-ice-ocean simulations. Different groups run or develop coupled Arctic RCMs (model RCAO from SMHI; model RASM from Univ. of Colorado, Boulder and Iowa State University; model COAWST from Uni Research Climate Norway; model HIRHAM-NAOSIM from AWI; model HIRHAM-HYCOM from DMI). Era-Interim- and GCM-driven runs are planned for the coupled model simulations.
Additional groups (model CRCM5 from the Université du Québec à Montréa, Canada; model RACMO from Univ. Utrecht, KNMI, Netherlands) plan to participate with atmospheric RCM simulations.
More Antarctic simulations are planned (model HIRHAM from DMI; model RACMO from Univ. Utrecht, KNMI; model COSMO-CLM from Univ. Leuven, Belgium).
Points of contact:
John Cassano, University of Colorado, USA
Annette Rinke, Alfred Wegener Institute, Germany
If you are interested in receiving regular updates on Polar CORDEX, you can subscribe to our mailing list (polar-cordex(at)climate-cryosphere.org) by sending an email to gwen(at)climate-cryosphere.org