CLIMARES, NERSC, October 2009 Arctic climate and future scenarios Ola M. Johannessen and Mats Bentsen Nansen Environmental and Remote Sensing Center

CLIMARES, NERSC, October 2009

Arctic climate and future scenarios

Ola M. Johannessen and Mats Bentsen

Nansen Environmental and Remote Sensing Center


Arctic Climate System

Warm surface watersCold Arctic watersCold deep waters River runoff

100 Gt/year = 0.3 mm/yr

• Warming• Ice/snow melting• Increase run-off• Wildcard - Greenland Ice Sheet• Deep water formation conveyour belt• Strong natural variablity



Bergen Climate Model (BCM)Developed by the Nansen Center, the University of Bergen, and the Bjerknes Center. Development began in 1999 and it contributed results to CMIP3 (used for the IPCC AR4 assessment report).

Model components:

• Atmosphere: Action de Recherche Petite Echelle Grande Echelle (ARPEGE, research project on small and large scales).

• Land: A simple soil model incorporated in ARPEGE.

• Sea-ice: Originally the NERSC sea-ice model was used. Recently the sea-ice model GELATO, developed at Meteo France, has been incorporated. Both are handled as a subroutine call from MICOM.

• Ocean: Miami Isopynic Coordinate Ocean Model (MICOM) extensively modified at the Nansen Center.

• Atmospheric chemistry: Only prescribed concentrations of chemical constituents.

• Ocean Carbon Cycle: None.

• Coupler: OASIS 2.2.

• Ice sheet: None.


Status of Bergen Climate Model• BCM is the only Norwegian climate model in this class of model

complexity.

• BCM is still needed in many projects.

• Modifications and tuning of BCM and replacing the sea-ice model with GELATO have eliminated a cold bias of surface temperature, improved sea-ice realism, and reduced drift compared to IPCC AR4 simulations.


A BCM simulation with natural forcing

Courtesy: Odd Helge Otterå


A BCM simulation with natural and anthropogenic forcing

Courtesy: Odd Helge Otterå


Temperature

Johannessen et al. 2004



BCM simulations of 20th century with natural forcing

Courtesy: Lingling Suo and Odd Helge Otterå


BCM simulations of 20th century with all forcings



Comparison of BCM simulations and observations


CO2 (ppm)

0°C

-8°C

280 ppm

200 ppm

5.8°C

1.4°C

960 ppm

550 ppm

Temperatur (oC)

CO2 (ppm)

0°C

-8°C

280 ppm

200 ppm

5.8°C

1.4°C

960 ppm

550 ppm

Temperatur (oC)

650,000 år 1850 2008 2100

• Today: Highest level in 850.000 year• Year 2100: Highest level in 20 million yearsThe increase is mainly caused by (about 80%) burning of

coal, oil, and gas; the rest is mainly caused by deforestation and changes in land use

About 20% of the anthropogenic CO2 emissions will remain in the atmosphere for more than 1000 yearsThe CO2 emissions of today will continue to have an impact on the climate for a long time

850,000 år 1850

Observed and expected atmospheric content of CO2

850,000 år

Future climate scenarios

IPCC 2007

+ 3 ºC: Irreversible changes

+ 2 ºC compared to 1850: EU target

Arctic Sept Sea Ice Extent

Stroeve et al. 2007

Red: observedBlack: model esemble


In collaboration with NERSC, the carbon cycle group at the Bjerknes Center and the University of Bergen have extended BCM with the Hamburg Ocean Carbon Cycle Model (HAMOCC) and the Lena-Potsdam-Jena land carbon cycle model (LPJ) to form BCM-C. Atmospheric CO2 concentration is updated annually.

Bergen Climate Model with carbon cycle (BCM-C)


Surface temperature with A2 scenario CO2 emissions

Courtesy: Jerry Tjiputra


Ocean and land CO2 uptake with A2 scenario emissions

Courtesy: Jerry Tjiputra


From BCM to a Norwegian Earth System Model• Desire to unify climate model and analysis tools in Norway to establish a

common ESM.

• To meet demands in various projects and IPCC AR5 scenario integrations, the model system should include biochemical cycles and a more sophisticated atmospheric chemistry.

• Be able to exploit the computing recourses available now and in the near future.

• The development plan for ARPEGE was not satisfactory: No finite volume version planned or other means to improve conservation.

Small development staff.

No plan to include interactive atmospheric chemistry.


NorESM framework and model componentsNorESM is based on a development version of CCSM4 from the National Center for Atmospheric Research (NCAR), Boulder, USA.

Model components:

• Atmosphere: Community Atmosphere Model (CAM 3.5.39).

• Land: Community Land Model (CLM 3.6.02).

• Sea-ice: Community Sea-Ice Model (CSIM/CICE 4).

• Ocean: Miami Isopynic Coordinate Ocean Model (MICOM) extensively modified at the Nansen Center.

• Atmospheric chemistry: Chemistry-aerosol-cloud package in CAM by University of Oslo and met.no.

• Ocean Carbon Cycle: Hamburg Model of Ocean Carbon Cycle (HAMOCC) adopted for use with an isopycnic ocean model.

• Coupler: CPL 7.

• Ice sheet: Currently none, but NCAR and LANL are working on this.


CLM

CAM

CICE

HAMOCCMICOM

Atmospheric chemistry

Components in blue communicate trough a coupling component. Components in red are subroutines of blue components.

River routing

NorESM framework and model components


Coupled Model Intercomparison Project 5 (CMIP5)This project will produce simulations that will form the basis of climate modeling information to the IPCC AR5 report planned for 2013.

Two distinct focuses for proposed experiments:

• Long term simulations (century time-scale).

• Near-term simulations (decadal time-scale).

The long term simulations can be grouped as follows:

• Control, historical and AMIP simulations.

• Future climate projections, forced by prescribed concentration scenarios.

• Past and future climate simulation, forced by prescribed emissions.

• Simulations for feedback analysis and understanding model differences.

• Ensembles of historical and AMIP simulations.

• Simulations for climate change detection and attribution studies.

Documents

CLIMARES, NERSC, October 2009 Arctic climate and future scenarios Ola M. Johannessen and Mats Bentsen Nansen Environmental and Remote Sensing Center