ERA-20C Notes, Questions, and Discussion

Greetings

I read a recent reply to Yiyi's question (10/2017 comment #5401) regarding ERA-20C by Paul Berrisford, "For most applications you would use the monthly means of daily means. You would only use the synoptic means if you wanted to restrict your attention to a particular point in, or portion of, the diurnal cycle."

Can a month of monthly means (forecasts) and a month of synoptic means (forecasts) can be used interchangeably? Are there applications where one might be preferred? I assume that the comparison must be MODA forecast to SYN forecast, and AN to AN, if the forecasts contain only model output and the analysis contains assimilation?

-thanks in advance

Good moring!

We are working with 20CR and ERA20C on Shclimate dynamics. We observe some important differences prior to 1950 between both reanalysis. We would like to know when and where ship log data  is included in ERA20C between 1905 and 1950 south of 30S.

Thanks!