WCRP CORDEX: Other Regions

William J. Gutowski, Jr. Iowa State Univ., USA

Linda O. Mearns NCAR, USA

Details at: http://wcrp-cordex.ipsl.jussieu.fr/ (Search: “WCRP CORDEX climate”)

Progress in Various Regions (Examples) 1. Euro-CORDEX (9 distinct RCMs + variants)

- Runs at 0.44˚, 0.22˚ and (in process) 0.11˚ 2. Med-CORDEX (9 RCMs, 12 A-O RCMs)

- Add to original regions - Built off funded program

3. MENA-CORDEX

- Mtg. @ WCRP CORDEX Brussels (Nov 2103) 4. Arctic (~ 5 RCMs) & Antarctic

- Workshop March 2012 - Mtg. @ WCRP CORDEX Brussels (Nov 2103)

Progress in Various Regions (Examples) 5. East Asia (7 RCMs)

- Built partly off APN RMIP program - Workshops: Sep 2011, Nov 2012, Brussels 2013

6. South Asia (6 RCMs)

- Workshop Feb 2012 - Workshop Aug 2013

7. Southeast Asia

- Self-organizing among several countries - Mtg. @ WCRP CORDEX Brussels (Nov 2103)

Plus: CORDEX Statistical Downscaling Workshop

- ICTP Trieste, 26-27 September 2013

What’s Been Done for North America? 1. UQAM (René Laprise) – 0.44˚

1989 – 2008: ERA-Interim 1950 – 2100: CanESM & MPI GCMs Test runs at 0.11˚

2. Météo-France (Philippe Lucas-Picher) – 0.5˚

1989 – 2008: ERA-Interim M-Fr may do GCM-driven case(s)

3. CCCma – 0.44˚ and 0.22˚

CanESM2 driving CanRCM4 4. RegCM (Iowa State, Ray Arritt) – 0.5˚

1989 – 2008: ERA-Interim 5. Related activities at UK Met Office, Argonne and Univ. AZ

working to coordinate with them

WCRP CORDEX: ~ North America Program ~

Executive Committee W. J. Gutowski, Jr. – Iowa State Univ. (Co-Chair)

Linda Mearns – NCAR (Co-Chair) Lawrence Buja – NCAR

Dennis Lettenmaier – Univ. WA Ruby Leung – PNNL

Gregg Garfin – Univ. AZ Details at: http://wcrp-cordex.ipsl.jussieu.fr/

(Search: “WCRP CORDEX climate”)

CORDEX North America Program

Executive Committee: Mearns, Gutowski (chairs) Behar, Buja, Garfin, Leung, Lettenmaier

Science Committee: Mearns, Gutowski, Hall,

Anderson, Leung, Laprise, Christensen, Barsugli Applications Committee: Behar, Garfin, Kaatz,

Barsugli, Ammann, Ruane, Yates, Winter … Services Committee: Barsugli, McGinnis, …

•  5 different RCMs •  6 different GCMs •  150 years 1950-2100 each simulation •  High representative concentration pathway

(RCP 8.5) (future scenario) •  Two spatial resolutions 25 km and 12 km •  ERA-Interim runs (20 years) at 50, 25, 12 km •  In planning phase – proposal being written

Some Basics

Priorities of Uncertainties •  Sampling range of GCMs •  Sampling range of RCMs

– And investigating multiple resolutions •  Internal variability (i.e., sampling multiple

realizations of single GCM) – This element has been under-explored in

GCMs and RCMs •  RCPs - lower priority – not important until

after 2050 – much might be gleaned from pattern scaling from one RCP to another

Activities •  NA-CORDEX Meetings Dec. 2012 in San Francisco,

February 2013 and June 2013 at NCAR – to further develop integrated plans/proposal

•  Survey of potential users – to determine more detailed user needs

•  Coordination with groups already producing simulations (e.g., French, Canadians, British)

•  Discussion with agency program managers on level of interest

•  DOE-funded workshop being planned for early 2014 involving other agencies as well

EXTRA SLIDES

WCRP CORDEX North America Program Using an ensemble of simulations, we will attain these goals: ­ Determine with statistical rigor levels of confidence in

regional climate information; ­ Assess the added value of downscaling for decision makers

and other applications communities; ­  Identify key processes and climate-system sensitivities for

North American climate change; ­  and in achieving these goals, Produce strategies for optimizing resources

to obtain climate change information efficiently; ­  Develop a co-learning environment among its participants for producing

the knowledge needed to advance regional climate downscaling and its applications.

Overall - North America CORDEX will provide leadership to the global CORDEX community and thus strengthen CORDEX.

Science Questions (Examples) 1. How do we measure the added value of downscaling, especially for applications, through the ensemble of CORDEX simulations? 2. How will CORDEX extend lessons learned in NARCCAP? 3. What resolutions are needed for key physical processes? 4. What is the optimum balance of the types of runs performed to efficiently sample the full uncertainty space (resolution, ensemble size, concentration pathways, GCMs, RCMs, internal variability)? Applications Questions (Examples) 1. What are key metrics for assessing the value of climate simulations and climate change information? 2. What are effective modes of interaction across communities that optimize appropriate use of climate information?

WCRP CORDEX North America Program

Simulation Plan

•  Balance matrix of cases following statistical factorial design (lesson from NARCCAP)

•  Do at least 3 resolutions (50-, 25-, 12-km) sufficiently to estimate added value of increasingly finer resolution

•  GCM (CMIP5, 150 yr) boundary conditions + ERA-Interim (CORDEX protocol, 20 yr)

•  Impact of GCM internal variability (some GCMs saved multiple realizations)

•  Selected further downscaling to cloud-permitting and cloud-resolving scales

•  Selection of GCMs: Range of climate sensitivity; quality of historical runs; quality of impt. features like ENSO, NAO; development history

•  Selection of RCMs: 5 from NARCCAP, updated (WRF, RSM, RegCM, CRCM, HadRM); possibly additional European RCM?

•  Statistically downscale from any of the RCM resolutions

WCRP CORDEX North America Program

Analysis Plan

•  Side-by-side comparison of multiple downscaling methods: RCM produced by NA CORDEX, statistical, hi-res GCM

•  Identification and analysis of key physical processes underlying the regional climate changes

•  Diagnosis of characteristics of unforced, internal variability: variation in space (differences across North America), time (e.g., variation with season, ENSO cycle, etc.), spatio-temporal scale dependence.

•  Determination of optimal approaches to obtaining regional information •  Exploration of different bias correction methods

WCRP CORDEX North America Program

Simulation Plan – ERA-Interim Baseline

WCRP CORDEX North America Program

ERA-Interim simulations contribute, in part, to the baseline CORDEX protocols: global distribution of 50-km simulations using ERA-Interim. ERA-Interim simulations also contribute to the assessment of added value from increasing resolution.

GCM Simulation Option 1: Full matrix @25, half matrix @12

WCRP CORDEX North America Program

* - 2 GCMs will provide boundary conditions from 4 realizations, to allow exploration of internal variability’s influence on uncertainty and added value.

GCM Simulation Option 3: Half matrix @25, 1/3 matrix @12

WCRP CORDEX North America Program

Options 1 and 3 represent opposite ends of possible simulation plans. An option 2 uses a half matrix for both res. More sparse matrices limit the statistical detail one can extract.

Opportunities 25-km Opportunity: 1. Downscale CMIP5 GCMs running at average resolution of about 1.8 deg. 2. Provide boundary conditions for higher resolution at both 12 km and 4 km. 3. At the approx. resolution of co-op observational data 12-km Opportunity: 1. Grid spacing approx. same as BCSD data set used by many 2. Finer resolution of some features

Limitations 1. U.S. does not have dedicated regional modeling centers 2. Computing cost increases inversely with cube of resolution, data storage inversely with resolution squared 3. Optimization of RCMs for massively parallel computation? 4. Finer grids (e.g., 12-km) cannot downscale directly from nearly all CMIP5 GCMs

WCRP CORDEX North America Program