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
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
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.
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.
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.
ECMWF S2S forecasts 20150105
ECMWF S2S forecasts 20150430
JMA S2S forecasts, 20150106
JMA S2S forecasts, 20150429
Thank you for attention!