1. Long Range Forecast Transient Intercomparison Project (LRFTIP-A)
M.A. Tolstykh (1,2), T.V.Krasjuk (2)
1)Institute of Numerical Matematics Russian Academy of Sciences;
2) Hydrometcentre of Russia
W. Merryfield (3)
Canadian Center for Climate Modelling and Analysis, Canada

2. Motivation
Beyond tropics, the atmosphere leads the ocean at subseasonal and seasonal time scales.
The ‘pure’ atmospheric model developers are requested to minimize T2m, precip errors but often not the surface heat flux (or surface stress) errors.
It is important to reduce the atmosphere model biases
To do so, we have a lot of information in existing archives

3. Proposal. What to look at:
Daily accumulated precipitation
Daily (accumulated 24-hr) surface shortwave and longwave  downward radiation fluxes and surface wind stress components
Sea surface temperature (daily)
These characteristics for the first forecast month should be integrated over the defined regions.
Data should be averaged over hindcasts years.
At least, four different initial months covering all seasons (ideally including February, May, August and November ) should be included, as in CHFP.

4. Proposal (contd.)
Data sources: Daily data from existing seasonal hindcast archives such as the CHFP, ENSEMBLES, NMME Phase 2 and ongoing S2S projects can be used.
First, the ‘climatology’ used by each center should be calculated; then the anomalies.
In addition to global diagnostics, 3 regions are proposed for this diagnostics:
Tropical Pacific ocean (10S-10N, 150E-90W)
North-Atlantic region (15N -75N, 80W-20E)
 Tropical Atlantic (10S-10N, 50W – 0E)
The initialization method should be reported.

5. Some preliminary results from S2S archive
Technical details: in future S2S ECMWF data portal plans to provide `on the fly’ GRIB2 to NETCDF CMIP-compliant conversion, currently, only GRIB2 data are available
Not all data from the centres participating in the project have been processed yet.

6. ECMWF S2S forecasts

7. ECMWF S2S forecasts

8. JMA S2S forecasts,

9. JMA S2S forecasts,

10. Thank you for attention!