Transcript Forcing

Coordinated CESM/CanESM Large
Ensembles for the CanSISE Community
Paul Kushner
Department of Physics
University of Toronto
Purpose of this Discussion
• CanSISE Theme B and Deliverable 3:
Attribution of Climate/Cryospheric Events (ACE/ACRE)
– Quantify probability of extremes in presence or absence of
anthropogenic influence (FAR).
– E.g. what is the fraction of risk attributable to human
influence of the 2007 vs. the 2012 sea ice minimum?
• Create large initial condition ensembles of historical
and projected forcing simulations.
– Coordinated between CanESM (CCCma) and NCAR CESM1
(Toronto).
– Carry out attribution runs with selected radiative forcings.
• Ensemble size large enough to simultaneously estimate
– forced response and
– probability distribution associated with internal variability.
Purpose of this Discussion
• But we can use such runs for many other
purposes than ACE/ACRE!
– Let’s look on them as a community resource.
– Consider the design and diagnostic aims.
• To jog ideas I will review some applications of
the large ensemble approach, then talk about
our proposed experiments.
Distribution of
Global Temperature
Trends in CESM
Large Ensemble
(Kay et al. 2014,
submitted to BAMS)
Attributing changes in
extreme temperatures to
model uncertainty
versus internal variability
(Fischer et al. 2014,
Nature Climate Change)
Temperature
Anomaly
Communicating
uncertainty in
regional trends
arising from internal
variability
(Deser et al. 2012,
Nature Climate
Change)
Delworth & Knutson 2000
Deser et al. 2012
Analyzing
cryospheric trends
in context of
internal variability
and observational
uncertainty.
(Mudryk et al. 2013,
Climate Dynamics)
Several Large Ensemble Projects
Model
Time Period
Forcing
N
Projects
CCSM3
2005-2065
A1B
Projection
40
Deser et al.,
Teng/Branstator
CCSM4
1955-2010
Historical
40
Mudryk et al.
CESM1-CAM5
1950-2100
Historical/rcp 21
8.5
Fischer et al.
CESM1-CAM5
1920-2080
Historical/rcp 30 (NCAR)
Kay et al.
8.5
1 + 6 (UofT)
CanESM and NCAR
CESM (U of T)
1960-2020
HistoricalALL FORCE
HistoricalNAT
50
CanSISE Theme B
In red are shown runs to be done this year.
Design Discussion
Model version
• CanESM – which version?
• CESM1 – CAM5: 2 degree atmosphere, 1 degree ocean
Forcing
• Generally, use each model’s forcings.
• But CESM has specially developed stratospheric ozone from
WACCM with realistic Antarctic Ozone Hole.
• Should this be used for CanESM?
pictrl spin-up
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 2 degree on SciNET (Compute
Canada allocation)
Initialization
and generation
of realizations
1850-1950, branch at 1950, analysis 1960-2020
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 on SciNet
• Standard perturbation methods to generate realizations.
Data saved
•
•
•
•
Diagnostic set developed for CESM project.
Extensive, but a good starting point.
NetCDF data compression reduces data by factor of 2-4.
Each 3-D variable saved monthly requires ~15-20GB for 2
degree model resolution on 30 levels.
• What output should be saved and where should it be saved?
Design Discussion
Model version
• CanESM – which version?
• CESM1 – CAM5: 2 degree atmosphere, 1 degree ocean
Forcing
• Generally, use each model’s forcings.
• But CESM has specially developed stratospheric ozone from
WACCM with realistic Antarctic Ozone Hole.
• Should this be used for CanESM?
pictrl spin-up
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 2 degree on SciNET (Compute
Canada allocation)
Initialization
and generation
of realizations
1850-1950, branch at 1950, analysis 1960-2020
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 on SciNet
• Standard perturbation methods to generate realizations.
Data saved
•
•
•
•
Diagnostic set developed for CESM project.
Extensive, but a good starting point.
NetCDF data compression reduces data by factor of 2-4.
Each 3-D variable saved monthly requires ~15-20GB for 2
degree model resolution on 30 levels.
• What output should be saved and where should it be saved?
Design Discussion
Model version
• CanESM – which version?
• CESM1 – CAM5: 2 degree atmosphere, 1 degree ocean
Forcing
• Generally, use each model’s forcings.
• But CESM has specially developed stratospheric ozone from
WACCM with realistic Antarctic Ozone Hole.
• Should this be used for CanESM?
pictrl spin-up
(multi century)
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 2 degree on SciNET (Compute
Canada allocation)
Initialization
and generation
of realizations
1850-1950, branch at 1950, analysis 1960-2020
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 on SciNet
• Standard perturbation methods to generate realizations.
Data saved
•
•
•
•
Diagnostic set developed for CESM project.
Extensive, but a good starting point.
NetCDF data compression reduces data by factor of 2-4.
Each 3-D variable saved monthly requires ~15-20GB for 2
degree model resolution on 30 levels.
• What output should be saved and where should it be saved?
Design Discussion
Model version
• CanESM – which version?
• CESM1 – CAM5: 2 degree atmosphere, 1 degree ocean
Forcing
• Generally, use each model’s forcings.
• But CESM has specially developed stratospheric ozone from
WACCM with realistic Antarctic Ozone Hole.
• Should this be used for CanESM?
pictrl spin-up
(multi century)
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 2 degree on SciNET (Compute
Canada allocation)
Initialization
and generation
of realizations
1850-1950, branch at 1950, analysis 1960-2020
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 on SciNet
• Standard perturbation methods to generate realizations.
Data saved
•
•
•
•
Diagnostic set developed for CESM project.
Extensive, but a good starting point.
NetCDF data compression reduces data by factor of 2-4.
Each 3-D variable saved monthly requires ~15-20GB for 2
degree model resolution on 30 levels.
• What output should be saved and where should it be saved?
Design Discussion
Model version
• CanESM – which version?
• CESM1 – CAM5: 2 degree atmosphere, 1 degree ocean
Forcing
• Generally, use each model’s forcings.
• But CESM has specially developed stratospheric ozone from
WACCM with realistic Antarctic Ozone Hole.
• Should this be used for CanESM?
pictrl spin-up
(multi century)
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 2 degree on SciNET (Compute
Canada allocation)
Initialization
and generation
of realizations
1850-1950, branch at 1950, analysis 1960-2020
• Does this exist for CanESM version used?
• To be done in 2014 for CESM1 on SciNet
• Standard perturbation methods to generate realizations.
Data saved
•
•
•
•
Diagnostic set developed for CESM project.
Extensive, but a good starting point.
NetCDF data compression reduces data by factor of 2-4.
Each 3-D variable saved monthly requires ~15-20GB for 2
degree model resolution on 30 levels.
• What output should be saved and where should it be saved?
Conclusion
• Large initial condition ensembles involve work to
coordinate, significant computation, data resources.
• They can add value to traditional CMIP sets, but this
requires good planning/coordination. Let’s make sure
to coordinate well.
• Tentative timeline:
– June 2014: finalize design
– August 2014: pictrl done
– December 2014: 5-10 realizations done, initial
comparisons.
– April 2015: full sets done.
Discussion