Evaluation of IPCC Global Climate Models for North Pacific Marine Ecosystem

Applications Nicholas A. Bond

University of Washington/JISAO

Outline

• Excerpts from recent work (e.g., Capotondi et al. 2012 and Furtado et al. 2011)

• Results from some CMIP3 runs along with a few CMIP5 runs under the RCP8.5 scenario

• Musings

Capotondi et al. (2012)2050-2099 vs. 1950-1999

Capotondi et al. (2012)

mm per day psu

Capotondi et al. (2012)(Surface to 200 m)

Potential density (kg/m3)

Changes in February Mixed Layer Depth from Present to 2040s(standard deviations)

Changes in Mean August Mixed Layer Depth from Present to 2040s(standard deviations)

Furtado et al. 2011

Skill of Global Climate Model (DHFP1) for PDO Prediction Lienert (Ph.D., 2011)

*Both

*Z

**Z

*Z

*Transport

Transport*

Temperature X-Section

Parameters Evaluated• Bering Sea - Flow through Unimak Pass

(Nutrient supply); Spring Winds (Larval flatfish transports); Summer SST & Wind Mixing (Sustained productivity); etc.

• Gulf of Alaska - Along-coast winds (Larval fish distribution and abundance); Precipitation (Upper ocean baroclinity and eddy generation)

• NE Pacific - Coastal upwelling (Productivity); Zonal winds (LTL communities); Pycnocline depth; Upper-ocean transports

Newport

Alaska PeninsulaVancouver Is.

PAPA

Seward Line

*

SODA ECHAM5 PCM1

MirocM MirocH MRI

Feb

Aug

Average Temperatures 1990-2000

SODA CCCMAT47_1 CCCMAT47_2

CCCMAT47_3 CCCMAT47_4 CCCMAT47_5

Feb

Aug

Average Temperatures 1990-2000

*

Mean Zonal Currents in Vertical Plane along 170 W from SODA

Mean Zonal Currents in Vertical Plane along 170 WFrom HadGEM2CC and GFDLESM2G models

Absolute Model Errors

Quasi-quantitative Assessment of Global Climate Model Capabilities

Considerations• Recent research (e.g., Furtado et al. 2011)

indicates that current GCMs, in general, do not replicate observed ENSO-North Pacific linkages that well

• Past performance no guarantee of skill in future projections (e.g., Reifen & Toumi 2009)

• Unclear whether weighting or even omitting ensemble members provides any meaningful benefits (e.g. Pierce et al. 2009)

• Inter-model dominates intra-model variability for projections longer than 1-2 decades

• Lack of community consensus on best practices in the use of GCMs for regional applications

Final Remarks• From present to mid-21st century, climate change

liable to be dominated by thermodynamic effects as opposed to dynamic effects (e.g., winds).

• Open questions: (1) Are the ocean components of global climate models sufficient for climate/ecosystem studies? (2) Are the new CMIP5 models significantly better than the CMIP3 models? (3) What is the best way to use existing climate model simulations for regional applications?

• The output from global climate models (perhaps subject to statistical downscaling) can complement that from vertically-integrated numerical models with full dynamics.