The Working Group on Coupled Models (WGCM) Report to JSC, 2010 Sandrine Bony & Jerry Meehl WGCM co-chairs Antalya, Feb 2010.

The Working Group on Coupled Models (WGCM)Report to JSC, 2010

Sandrine Bony & Jerry MeehlWGCM co-chairs

Antalya, Feb 2010

Review and foster the development of coupled climate models (and now ESMs)

Coordinate model experiments and inter-comparisons to:- better understand natural climate variability- predict the climate response to natural & anthropogenic perturbations

Promote and facilitate model validation and diagnosis of shortcomings

WGCM Mission

A balance between :

Predicting – Evaluating - Understanding

Coordinated Model Experiments :

CMIP3 : a big boost to climate science

• More than 500 publications

• More than 765 TB downloaded

• More than 3,000 users

Aug 2009Jan 2007(AR4 WGI)

Nov 2004

Courtesy of Bob Drach & Karl Taylor, PCMDI

Better inform decisions on climate change adaptation and mitigation

Integrate Earth System Modelling

Better assess robust and uncertain aspects of climate change

Facilitate model evaluation and assess confidence in model projections

+ improvements on the infrastructure side

From CMIP3 to CMIP5 :

What should be improved ?

… this led to CMIP5

Promotes a standard set of model simulations in order to : evaluate how realistic the models are in simulating the recent

past provide projections of future climate change on two time

scales understand some of the factors responsible for model

differences

Two timescales and two sets of science problems

Will be assessed by the IPCC AR5

Taylor et al. 2009, http://cmip-pcmdi.llnl.gov/cmip5/Near-Term :(next 3-4 decades)

→ decadal climate predictability

→ ocean initialization

→ impact volcanos

→ regional climate changes (high resol) & climate extremes

→ air quality changes (aerosols, chemistry)

Long-Term :(past to 2100 & beyond)

→ evaluation of climate models(recent past, A-Train, paleo)

→ detection & attribution

→ climate change scenarios

→ climate sensitivity, radiativeforcing and physical

feedbacks (e.g. clouds)

→ biogeochemical feedbacks(e.g. carbon, chemistry)

CMIP5 : a framework for climate change modeling over the next 5+ years

Promotes a standard set of model simulations in order to : evaluate how realistic the models are in simulating the recent

past provide projections of future climate change on two time

scales understand some of the factors responsible for model

differences

Two timescales and two sets of science problems

Will be assessed by the IPCC AR5

Taylor et al. 2009, http://cmip-pcmdi.llnl.gov/cmip5/

CMIP5 : a framework for climate change modeling over the next 5+ years

AMIP

“time-slice”

CORE

For computationally demanding models : very high resolution or very complex models, or new generation

ofclimate models (MMF, global CRMs) :

Prescribed SST time-slices (1979-2008 + 2026-2035) + idealized experiments (e.g. aqua-planet, +4K,

4xCO2)

→ regional effects of climate change

→ explore the impact of higher resolution on climate simulations : mean & variability,

extremes, AND sensitivity to external perturbations.

Coupled carbon-cycle climate models only

All simulations are forced by prescribed concentrations except those “E-driven” (i.e., emission-driven).

ClimateProjections

Understanding

D & A

ense

mbles

Control, AMIP, &

20 C

RCP4.5, RCP8.5

ensembles: AMIP & 20 C

natural

-only,

GHG-only

individual

forcing

RCP2.X, RCP6 extend RC

P4.5 to

2300

extend RCP8.5 & RCP2.X to

2300

ense

mbl

e of

ab

rupt

4xC

O2 5

-yr

runs

aqua planet

(clouds)

unform ΔSST

(clouds)

Mid

-Hol

ocen

e &

L

GM

last

mill

enni

um

E-driven RCP8.5

E-driven control & 20 C

patterned

ΔSST

(clouds)

aerosol fo

rcing ca

.

2000

AC&C4

(chem

istry)

1%/yr CO2 (140 yrs)

abrupt 4XCO2 (150 yrs)

fixed SST with 1x & 4xCO2

radiation code sees 1xCO2 (1% or 20C+RCP4.5)

carbon cycle sees 1XCO2 (1% or 20C+RCP4.5)

Model Evaluation

Example of CMIP5 Long-Term Experiments

An important focus put on model evaluation and understanding...

... In collaboration with many WCRP/IGBP partners

Detection-Attribution(IDAG)

Paleo(PMIP, IGBP-PAGES)

Cloud andmoist processes

(CFMIP-GCSSWGNE)

Carbon-climate feedbacks(C4MIP, IGBP-AIMES)

Integrated AssessmentConsortium (IAM),

connection to WG-III

+ Satellite simulators& process

diagnostics (CFMIP-GCSS)

Chemistry, aerosols(SPARC, AC&C)

Example of CMIP5 Long-Term Experiments

At least 21 global modeling groups will participate in CMIP5. Likely that about 5 groups will have50 km class AOGCMs for decadal prediction, at least 10 groups will have ESMs, several groups will have high-resolution AGCMs (<50 km).

• The full sets of forcings and boundary conditions, and the list of model outputs, have been finalized. • Simulations have now started in many modeling groups.

• Model outputs will be archived on the “Earth System Grid” (distributed grid technology) which is being deployed and tested now.

• An extensive documentation of the models and of model experiments will be available for CMIP5 through EU Metafor (standardized vocabulary and documentation), and US Earth System Curator projects (web-based tools for ingesting metadata).

• PCMDI will require agreement to the “terms of use” as part of the registration procedure. CMIP data will be divided into two classes: unrestricted and restricted-use (no restriction: 7 out of 12).

Analyses of model data will begin late 2010, and will be assessed by the IPCC AR5.

CMIP5 model simulations and analyses will continue well beyond AR5 deadlines.

Status and Timeline :

In parallel to CMIP5, many other climate model coordinated experiments

are being organized by the modelling community

– WGCM (PMIP, CFMIP..): paleo, clouds– WGNE/WGCM (Transpose-AMIP): evaluation of climate models in NWP mode- CLIVAR WGSIP, WGOMD : seasonal to interannual prediction, ocean– TFRCD (CORDEX) : regional– GEWEX GCSS (GPCI) : processes– SPARC & IGBP/IGAC (CCMVal, AeroCom..): chemistry & aerosols– IGBP/AIMES (C4MIP) : carbon feedbacks– … and much more!

+ WGNE/WGCM Metrics panel

Proposal for coordinated geo-engineering experimentswith stratospheric aerosols

by Ben Kravitz, Alan Robock et al.

Aim: explore the efficacy and risks of stratospheric geo-engineering with sulfate aerosols.

Demonstration project to be conducted by a few modeling groups. Coordination with SPARC? Not part of CMIP5. Received some feedback from WGCM last September.

Issues of particular interest : - robustness of the model responses to geo-engineering- response of the hydrological cycle, temperature patterns and stratospheric ozone- response to the stoppage of geoengineering after a few decades

Several experiments proposed for coupled ocean-atmosphere models including interactiveaerosols and chemistry :

- in combination of 1% increase CO2 per year, progressively balance the CO2 radiative forcing by a reduction of the solar constant - in combination of RCP 4.5 scenario: progressively balance the CO2 radiative forcing by

injecting stratospheric aerosols (or SO2) at the equator.- abrupt stoppage of geo-engineering after 50 years+ simpler idealized experiments to better understand inter-model differences

Interested modeling groups will perform these experiments this year. More groups mightjoin after this demonstration project. How should this be coordinated across WCRP?

BIG CHALLENGE :

How to improve our confidence in climate models ?

How to assess the credibility of model projections ?

LES modelsCloud Resolving Models

Single ColumnModels

3D-Climate ModelsNWP Models

High resolution global models(global CRM, MMF)

Global observational datasets

Field campaigns & instrumented sites

How to gain confidence in GCMs projections ?

(1) Bottom-Up approach : evaluate and improve the physical basis of climate models through large-scale and process-scale evaluations

Analysis & Understandingclimate change

Model projections

Model projections

LES modelsCloud Resolving Models

Single ColumnModels

3D-Climate ModelsNWP Models

High resolution global models(global CRM, MMF)

Global observational datasets

Field campaigns & instrumented sites

How to gain confidence in GCMs projections ?

(1) Bottom-Up approach : evaluate and improve the physical basis of climate modelsthrough large-scale and process-scale evaluations

(2) Top-Down approach : understand the models' results & identify critical processesto provide guidance for specific observational tests/process studies and model improvements

Analysis & Understandingclimate change

- Better interpret inter-model differences in current climate & climate projections

- Evaluate climate models over a wide range of scales and phenomena i.e. from weather to paleo time scales, from regional to global, from processes to climate, across all physical and biogeochemical components

- Explore how model formulation and present-day model performance translate to reliability of climate projections

→ a big challenge and a key focus of WGCM activities over the next few years, in collaboration with WCRP/IGBP partners

CMIP5 and associated modeling activities :an opportunity to develop both approaches,

especially the second one

A WGCM project supported by WCRP/CLIVAR and IGBP/PAGES

Coordinated by: P. Braconnot & S. Harrison

with S. Joussaume, B. Otto-Bliesner, A. Abe-Ouchi, A. Haywood, P. Valdes, G.Ramstein, K. Taylor, P. Bartlein, M. Kucera, J. Jungclaus

Main objectives: Coordinate paleoclimate modelling activities to :

- Understand the mechanisms of past climate change- Test whether climate models can represent a climate state different from the present-day

(Taylor et al. 2009)

e.g. Reconstructed SST anomalies at LGMMARGO: Nature Geoscience 2009

PMIP – Phase 3

Coordinated model experiments :

• PMIP3 / CMIP5 simulations :- Mid-Holocene (6 ka)

- Last Glacial Maximum (LGM, 21 ka)- Last Millenium

→ using the same model version than forCMIP5 simulations of present-day and

climate projections !

Data syntheses :

• Key periods

• Assess uncertainties in past reconstructions

PMIP database and website :

http://pmip2.lsce.ipsl.fr→ PMIP working groups also focus on otherkey periods (e.g. last inter-glacial 130 ka,Mid-Pliocene 3 Myr ago, etc)

Polar amplification : Continental vs ocean response :

Laîné et al. 20092xCO2

4xCO2

LGM

Elevation correction

Greenland ice core estimates

Antarctic ice core estimates

2xCO2

4xCO2

LGM

Elevation correction

Greenland ice core estimates

Antarctic ice core estimates

Masson-Delmotte et al, 2005

Temperature response over different ocean basins at LGM :

Otto-Bliesner et al. 2009

+ data models

Constraints on climate sensitivity

Change in precipitation inferred for Mid-Holocene (6 ka)over western Africa :

Constraints on the response ofthe hydrological cycle

Joussaume et al. 1999Braconnot et al. 2007

A WGCM project coordinated by : Mark Webb, Sandrine Bony, Christopher Bretherton, Steve Klein, George Tselioudis

Aims : Encourage coordinated research in the area of cloud-climate feedbacks.

Facilitate the evaluation of clouds simulated by climate models

Strong interactions between climate/process/observation/NWP communities

Cloud Feedback Model Inter-comparison Project Phase-2CFMIP-2 (www.cfmip.net)

Building bridges through the cloud communities

Assessment of cloud-climate feedbacks

Understanding Evaluation


GCM analysis througha hierarchy of models





Process studies(in-situ obs, LES/CRMs)




CFMIP/GCSS/CMIP5 model outputs at selected locations(118 locations, high-frequency, detailed cloud

diagnostics)

● ARM, CEOP, CloudNet instrumented sites● GPCI / Tropical West & South East Pacific / AMMA transects● Field experiments / GCSS case studies● Locations of large inter-model spread of cloud feedbacks (CMIP3)

GPCIAMMA

VOCALS

Oklahoma

Barrow

TOGA-COARE

ASTEX

GATE

SHEBA

SIRTAChibolton

Tibet

RICO

Darwin

CFMIP-GCSS Study of Cloud Feedback Mechanismsby using SCM/CRM/LES Models (CGILS, coordinated by Minghua Zhang)

Case studies of PBL cloud feedback mechanisms


Process studies(in-situ obs, LES/CRMs)

Satellite observations& simulators (COSP)




Cloud Vertical Distribution

LMDZ4+ SIM

CCCMA+ SIM

CALIPSO-GOCCPCAM3.5 + SIM

ECHAM5 + SIM

Overestimate:of high clouds

Underestimate of:- Tropical low clouds- Congestus clouds- extratropical mid-level clouds

OBS

0

0.3

Chepfer et al. (Calipso-Cloudsat workshop, Jul 2009)

Vertical distributions of radar reflectivities (CFADs)

(Bodas-Salcedo et al., in preparation)

CloudSat

Link available from www.cfmip.net

Observations useful for the evaluation of model clouds through COSP

Observations for CMIP5 Simulations

• The climate modeling community would greatly benefit from an easier and morecoordinated access to observations for model evaluation and analysis.

• Many individual initiatives worldwide (different MIPs, ARM, etc)

CMIP5 might be an excellent opportunity to foster a coordinated access to observations that are most useful for model evaluation.

• Recently, JPL (Joao Texeira, Duane Waliser, Jerry Potter, S Boland) launched such an initiative

- To provide the community of researchers that will analyze CMIP5 simulationsaccess to analogous sets of observational data.- Analogous sets in terms of periods, variables, temporal/spatial frequency- This activity will be carried out in close coordination with CMIP5 & modelling activities- It will directly engage the observational (e.g. mission and instrument) science teams tofacilitate production of the corresponding data sets.

Discussions already engaged with NASA. What about other providers of satellite and in-situ observations? To be discussed with WOAP and GCOS.

Conclusion

Trying to keep the balance between predicting, evaluating and understanding...

CMIP5 : - many new features : decadal, ESMs, high-resolution, satellite and process outputs..- strong partnership with WCRP partners and IGBP (joint WGCM-AIMES meeting)- huge effort for modeling groups and many other communities

Analysis of CMIP5 simulations : an opportunity to - build connections among modeling communities and between modeling,

processes and observation- address key science challenges e.g. assessing the reliability of model projections based on model evaluation

at different time scales. cf IPCC expert meeting on multi-model simulations- help interpret model deficiencies and guide the model development process (motivation for the Survey on model evaluation and improvement at last CLIVAR SSG).

Issues for JSC :

- coordination of observations for model evaluation (modeling – WOAP – GCOS panels)

- coordination & syntheses of different MIPs, evaluations and analyses across WCRP & IGBP

- CMIP5 analysis : recommendations? e.g. encourage coordinated analyses and syntheses about key topics cross-acronyms (strengthen connections + help AR5

authors)

WCRP-WWRP-THORPEX Consultation onWCRP-WWRP-THORPEX Consultation on

Model Evaluation and ImprovementModel Evaluation and Improvement

Sandrine Bony, Jerry Meehl, Anna Pirani (WGCM)Christian Jakob, Martin Miller (WGNE)

Ben Kirtman (WGSIP), Stephen Griffies (WGOMD), Tony Busalacchi (WCRP)

Background and Goal :

- Model errors and biases are key limitations of the skill of model predictionsover a wide range of time and space scales ;

- Not a new story. The increase of resolution and the addition of complexity in ESMs have not solved the problem.

- How to tackle the problem ? What should we do? What can we do ?

-> Bottom-up consultation of NWP/climate modeling groups, CLIVAR WGs/panels, WCRP/WWRP/IGBP projects

- Restructuration of WCRP : an opportunity to put recommendations into action.

More in a few minutes....