1. Rein Haarsma KNMI (lead) Malcolm Roberts Met Office (co-lead)
HighResMIP
Rein Haarsma KNMI (lead) Malcolm Roberts Met Office (co-lead)
Important weather and climate processes emerge at sub-50km resolution
They contribute significantly to both large-scale circulation and local impacts, hence vital for understanding and constraining regional variability
How robust are these effects?
Is there any convergence with resolution across models?
Need coordinated, simplified experimental design to find out
Global drivers
Regional variability
Feedbacks
to large
scale
Note: the use of both AMIP-style and coupled integrations – it is not necessary to do both, if that is not possible. An AMIP comparison would lead to significant increased understanding in itself.
Coupled models consist of pairs of control (using fixed 1950’s forcing) and experiment with historic and then projection forcings to 2050
Both the aerosol concentrations and the SST and sea-ice forcing datasets and tools will be supplied, as far as is possible – for AMIP-style the historic period will use HadISST, while the future will use the methodology of Mizuta et al from MRI.
Input to aerosol concentrations are expected from RFMIP.
Experimental protocol:
Global models – AMIP-style and coupled
Physical climate system only
Integrations:
Ensemble size: >=1 (ideally 3)
Resolutions: <25km HI and ~60-100km STD
Aerosol concentrations specified
Local processes
Impacts, extremes
e.g. Zhao et al, 2009; Haarsma et al, 2013; Demory et al, 2013

2. Malcolm Roberts, Met Office (coordinator) Pier Luigi Vidale, Univ
Malcolm Roberts, Met Office (coordinator) Pier Luigi Vidale, Univ. of Reading (scientific coordinator)
PRocess-based climate sIMulation: AdVances in high resolution modelling and European climate Risk Assessment
Goal:
to deliver novel, advanced and well-evaluated high-resolution global climate models (GCMs), capable of simulating and projecting regional climate with unprecedented fidelity, out to 2050.
To deliver:
innovative climate science and a new generation of European advanced GCMs.
improve understanding of the drivers of variability and change in European climate, including extremes, which continue to be characterised by high uncertainty
new climate information that is tailored, actionable and strengthens societal risk management decisions with sector-specific end-users
new insights into climate processes using eddy-resolving ocean and explicit convection atmosphere models
To run for 4 years from Nov 2015 including 19 partners across Europe, funded by the Horizon 2020 call SC Advanced Earth System Models
proj.badc.rl.ac.uk/primavera
Core integrations in PRIMAVERA will form much of the European contribution to CMIP6 HighResMIP
Note: the use of both AMIP-style and coupled integrations – it is not necessary to do both, if that is not possible. An AMIP comparison would lead to significant increased understanding in itself.
Coupled models consist of pairs of control (using fixed 1950’s forcing) and experiment with historic and then projection forcings to 2050
Both the aerosol concentrations and the SST and sea-ice forcing datasets and tools will be supplied, as far as is possible – for AMIP-style the historic period will use HadISST, while the future will use the methodology of Mizuta et al from MRI.
Input to aerosol concentrations are expected from RFMIP.

3. Modelling groups expressing interest in HighResMIP (at least for Tier 1 simulations)
Country
Group
Model
China
BCC
BCC-CSM2-HR
Brazil
INPE
BESM
Chinese Academy of Meteorological Sciences
CAMS-CSM
Institute of Atmospheric Physics, Chinese Academy of Sciences
FGOALS
USA
NCAR
CESM
Center for Earth System Science/Tsinghua University
CESS/THU
Italy
Centro Euro-Mediterraneo sui Cambiamenti Climatici
CMCC
France
CNRM-CERFACS
CNRM
Europe
EC-Earth consortium (11 groups)
EC-Earth
GFDL
Russia
Institute of Numerical Mathematics
INM
Japan
AORI, University of Tokyo / JAMSTEC / National Institute for Environmental Studies
MIROC6-CGCM
NICAM
Germany
Max Planck Institute for Meteorology (MPI-M)
MPI-ESM
Meteorological Research Institute
MRI-AGCM3.xS UK
Met Office
UKESM /HadGEM3

4. European HighResMIP resolutions (as part of PRIMAVERA)
Example resolutions which will definitely contribute to HighResMIP
Concentrate on horizontal resolution – keep vertical resolution the same
ECMWF is an NWP partner – present day simulations, extra ensemble members, and including very high resolution atmosphere simulations – we welcome other NWP centres’ submissions

5. Anticipated outcomes from this meeting
Agree to as much of the protocol as possible
Suggested way forward for any other aspects
Complete contact list to participate in GMD HighResMIP protocol manuscript (open April – December 2015)
PRIMAVERA starts 1 Nov – need protocol in place (and ideally tested) by then.

6. HighResMIP model configurations (1)
Parallel standard and high resolution integrations
STD likely to be default CMIP5/CMIP6-DECK resolution (~100km atmosphere resolution)
Hence DECK is benchmark for STD, HI is sensitivity test
HI being ~25km atmosphere resolution
Strongly encourage absolutely minimal differences between STD and HI configurations
Vital part of HighResMIP is to look for systematic differences with model resolution across multi-model ensemble
If extra tuning is made between different resolutions, it will make it extremely hard to pick apart the causes of differences
NOT a beauty contest to have the perfect HI model, we are most interested in the delta between resolutions
Similarly vertical resolution should be the same in STD and HI

7. HighResMIP model configurations (2)
Diagnostics list
Initial submission to CMIP6 for HighResMIP diagnostic list (having attempted to consult widely on required diagnostics)
Considerable number of extra high frequency (1h, 3h, 6h) diagnostics compared to CMIP5 list, to look at extreme processes in particular
Balance between scientific interest and manageable data volumes
Integration protocol (STD + HI)
Physical climate system only, minimal Earth System components
Tier 1: simple forced-atmosphere integrations using SST and sea-ice datasets to be provided
Tier 2: coupled simulations
Tier 3: extension of forced integration to 2100
Tier 4: aquaplanet
Tier 5: switch-on 4xCO2
Further discussions on more detailed aspects of protocol are ongoing, and will be published in GMD Special Issue later in 2015
Will also be published on HighResMIP wiki, together with helpful scripts for producing forcing datasets
Contacts:
Groups should get together for other Tier 3+ simulations (i.e. Those outside PRIMAVERA) to agree between themselves

8. HighResMIP protocol choices (1)
time period
Positives:
Longer period than typical AMIP period (overlap with CMIP6 DECK period will give extra ensemble member at low resolution)
Sample different periods of variability from the past, influence of phases of global modes of variability
Enables examination of decadal variability of different signs in tropical cyclones, Sahel rainfall etc
Idealised climate change signal several decades into future
Negatives
More expensive
Fewer ensemble members possible
Methodology for future period will be new, and not so interesting to some, e.g. NWP centres
signal to noise may be small

9. HighResMIP protocol choices (2)
All models use the same aerosol concentrations timeseries (provided by e.g. RFMIP)
Positives:
Multi-model comparison concentrates on physical resolution impact
Cleaner comparison than e.g. CMIP5
Influences on e.g. decadal variability the same
Negatives
Complicated with different aerosol schemes in different models
Providing aerosol datasets reliant on other projects, e.g. RFMIP
Models may need retuning from their standard aerosol climatology (though this may have been tuned at low resolution anyway)

10. HighResMIP protocol choices (3)
No retuning of model between low and high resolution
Positives:
Enables assessment of impact of horizontal resolution alone
Hence essential for the basic outcome of HighResMIP
High resolution expensive to tune anyway
Negatives
Higher resolution may not be ideal configuration
May be issues with TOA radiation
Document all changes made between resolutions
If insist, then show sensitivity studies so can understand what is resolution and what is tuning

11. HighResMIP protocol choices (4)
Diagnostics and data output at high frequency (more at 6hr, 3hr and 1hr) as well as column-integrated
Positives:
Significant new analysis becomes possible, including extreme processes and events (polar lows, Medicanes, intense precipitation, atmospheric rivers etc)
Encourages central analysis platform and sharing common analysis tools (rather than downloading huge volumes of data to local space)
Makes best use of HPC usage (run once, analyse many)
Negatives
Significant storage requirements (~400GB per model year at 25km resolution for priority 1 data)
More difficult to share data – no longer possible to store all diagnostics on CMIP5 data node (use of shared JASMIN platform will help this for coordinated analysis

12. SST and sea-ice protocol for forced-atmosphere (current plan)
present day
Based on HadISST
HadISST machinery can produce daily, 1/4˚ fields
Use fixed SST and sea-ice (rather than slab-ocean where model comparison will be harder)
Present day – 2050 (2100)
SST
Find period in past with similar phase of major modes of variability
Stitch this to the present day
Use trend in HadISST into the future (or use CMIP5 models for future trend)
Sea-ice
use Mizuta et al methodology to scale present-day sea-ice shape into future based on global SST change
KNMI methodology

13. Coupled model protocol (current plan)
1950 ocean initial condition
EN4 from observed profiles and analyses in 1950
Present day ocean (more observations but longer spin-up)
Coupled spin-up strategy
Start from 1950 state, run with 1950’s atmosphere forcing until TOA at acceptable level (both high and low resolution ocean) - ~decades
Start from present day, run with 1950’s atmosphere until TOA acceptable (both high and low resolution ocean) - ~decades
Use lower resolution model for spin-up and interpolate final ocean state to higher resolution – either ~decades or use CMIP6 DECK (will lock-in biases from low resolution)

14. Q&A