1. Data repositories
CHFP at CIMA is the WGSIP data repository: OPeNDAP, web interface, NetCDF3, CHFP convention.
Common complaint: Too many repositories (CHFP, EUROSIP, NMME, APCC, future S2S), different formats.
From WCRP’s JSC: “Action 53: To consider WGSIP plan/decision on engagement in ESGF”.
SPECS has adapted CMOR2 (Climate Model Output Rewriter version 2) to the needs of the climate-prediction community. The documentation is now developed and available from the SPECS web site, but still awaiting PCMDI’s blessing. Initial tests will be available from BADC, one of the main nodes of ESGF.
S2S’s data repository will follow the style from TIGGE (GRIB2, based on MARS). To make the data ESGF-compliant, a technical solution for an ESGF node to be able to map the files and an on-the-fly convertor to the CMOR2 NetCDF format will be needed.

2. Moving from current CHFP format
The current CHFP convention is not compatible with the CMOR and CF conventions. It also uses NetCDF3.
The SPECS convention evolves from the CMIP5 tables and uses the latest developments adopted by CORDEX: NetCDF4 (compression, half the size files), new experiment tables, double time axis, no ensemble dimension.
Explicit paths, experiment names, rip standard: EC-EARTH3/seaIceClimInit_series2/S /mon/ocean/vo/r1i1p1/vo_Omon_EC-EARTH3_seaIceClimInit_series2_r1i1p1_ nc
CIMA will have to become an ESGF data node and convert all the current CHFP data.

3. Moving from current CHFP format
Other differences with the CHFP format: slightly different time coordinates
variables:
double leadtime(time) ;
leadtime:units = "days" ;
leadtime:long_name = "Time elapsed since the start of the forecast" ;
leadtime:standard_name = "forecast_period" ;
double time(time) ;
time:bounds = "time_bnds" ;
time:units = "days since " ;
time:calendar = "gregorian" ;
time:axis = "T" ;
time:long_name = "Verification time of the forecast" ;
time:standard_name = "time" ;

4. Moving from current CHFP format
Other differences with the CHFP format: full description of grids
variables:
int j(j) ;
j:units = "1" ;
j:long_name = "cell index along second dimension" ;
int i(i) ;
i:units = "1" ;
i:long_name = "cell index along first dimension" ;
float lat(j, i) ;
lat:standard_name = "latitude" ;
...
lat:bounds = "lat_vertices" ;
float lon(j, i) ;
lon:standard_name = "longitude" ; …
lon:bounds = "lon_vertices" ;
float lat_vertices(j, i, vertices) ;
float lon_vertices(j, i, vertices) ;

5. Moving from current CHFP format
Other differences with the CHFP format: full-flavour global attributes
// global attributes:
:institution = "IC3" ;
:experiment_id = "seaIceClimInit" ;
:realization = "1" ;
:source = "EC-EARTH official release from SMHI" ;
:model_id = "EC-EARTH3" ;
:forcing = “CMIP5 standard" ;
:series = "series2" ;
:forecast_reference_time = " (T00:00:00Z)" ;
:physics_description = "N/A" ;
:associated_model = "N/A" ;
:initialization_description = "N/A" ;
:initialization_method = 1 ;
:physics_version = 1 ;
:creation_date = " T16:11:42Z" ;
:tracking_id = "6d22fb21-99c8-4a8b-b4c5-098db735f50e" ; …

6. What next
Obtain the official acceptance of PCMDI to this new convention (find a more appropriate name for it) and the incorporation of the SPECS patch.
Assess the work required for CIMA to become an ESGF node.
Prepare a convertor from current CHFP files to the new files (define values for the new attributes, experiment tables, one file per ensemble member). Also transfer the ENSEMBLES dataset. The size of the archive will be cut in half.
Investigate with IRI the ability of the CPT to read the data from the current OPeNDAP and the future ESGF node.
Work with S2S to ensure that there is compatibility. A CMOR-compatible GRIB2NetCDF convertor will be needed.
Lots of technical work, huge potential benefits visible in the short-term, some funding required.

7. New projects
WGSIP has three sub-projects under CHFP: IceHFP, StratHFP and GLACE2.
Other projects (e.g. S2S) are organised in science projects.
Possible science projects relevant to WGSIP’s activities are:
Teleconnections between tropics and extratropics
Drift/initial shock and verification within the first month
Others: climate services, verification, etc.
They can all create synergies with S2S.
How to proceed from here?