What are reforecasts?
Reforecasts are forecasts run using the same model version as real-time forecast for a number of past dates. More details here.
How to access S2S data efficiently?
In order to retrieve data efficiently users should follow instructions about S2S reforecasts retrieval efficiency.
Do you have any examples of S2S data retrieval scripts?
Find links here to efficient retrieval scripts for different S2S datasets via ECMWF Web API.
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