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(b) The production schedule of the Met Office forecasting system doesn't prescribe how to build an ensemble for a specific nominal start date. The following choices are currently in use for the data archived in C3SC3S products based on GloSea5 data:
FORECASTS: the most recent 50 members starting on or before the 1st of the month. (NOTE: The original daily/subdaily data from all the daily members, and not just those 50 used to produce the C3S forecast products, is processed and made available through the CDS). The monthly mean data is currently encoded and provided in the CDS as if all the members were initialized on the 1st.
HINDCASTS: 28 members (7 starting on the 1st of the month and 7 on each of the 9th,17th and 25th of the previous month)
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