Data issues on Met-Office and NCEP Seasonal forecast daily and subdaily data

Hi everyone,

I'm asking informations on the title's subject. I'm working with Met-Office and NCEP precipitation, temperature and radiation daily data:

1st I downloaded the monthly total precipitation. For the hindcast period I have 28 members for MET-Office and 24 members for NCEP;

2nd I downloaded the daily data of t2m and surface net radiation for the same providers. 

  • in the case of Met-Office daily data I have 7 members, from 101 to 107;
  • in the case of NCEP daily data I don't have any members, just all the data put together. After some manipulations I found out that those data are effectively 4 different members of the SF.

Why is there such inconsistency in the number of members between the monthly precipitation data and the daily temperature and radiation data? This issue does not occur for the other models.



I’m also interested, thanks.

The C3S Seasonal Forecast documentation describes the different ways the ensemble data are produced.
Also Seasonal forecasts and the Copernicus Climate Change Service contains background information of the different ways the ensemble members are produced, and Description of the C3S seasonal multi-system has details of the individual contributing systems.

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In addition to the documentation pages @Kevin_Marsh pointed out, for this specific question section 1 in the following page could be also useful: Guidelines to decode monthly C3S seasonal forecast data - Copernicus Knowledge Base - ECMWF Confluence Wiki

Also, it can help to go through the details about how “nominal” start dates are assigned in this page: Summary of available data - Copernicus Knowledge Base - ECMWF Confluence Wiki

Does that concept of “nominal start date” and its implementation help in understanding the differences between daily and monthly datasets?

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