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Find links here to efficient retrieval scripts for different S2S datasets via ECMWF Web API.
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What is the starting step of S2S parameters?
The instantaneous variables are archived from step 0, except for some centres (e.g. NCEP or BoM) who start at step=24 because they don't archive step 0 (step 0 has the same value as the re-analysis). Because of that the data at step 0 and step 24 are different and step=0 corresponds to the initial conditions. For accumulated variables (e.g. total Precipitation), step 0 is usually not archived because its value is equal to 0 and step=24 corresponds to the accumulation during the first 24 hours.
For MJO RMMS, the calculation for all models starts from step=24 (first common time step for all the models). It uses instantaneous winds at 850 and 200 hPa at step=24h and OLR accumulated over the first 24 hours