T2m over sea in CAMS reanalysis

Datasets and Usage CAMS - Datasets and Usage
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1

Dear All,

I am wondering about a strange jump in T2m over oceans at the beginning of 2017. From 2017 onward, T2M from CAMS is nearly equal to T2m from ERA5, but before 2017 they differ by up t several degrees:

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Over land there is no such jump. I suppose that the SST used as the lower boundary condition has been changed, being different from that used in ERA5 before 2017.

More important than the source of the difference are the possible implication. Is the CAMS reanalysis compatible with ERA5 before 2017? Can I combine data from both reanalyses?

Best regards,

Andreas Sterl

2

Hi Andreas; good to hear from you!
Did you try to plot differences for SST itself as well?
Regards,
Hans

3

Hello Hans,

Good to hear from you, too! I am ashamed, I did not look at SST, simply because I was sure that they are not in the CAMS data. But they are, and plotting them together with SST from ERA5 clearly reveals the problem

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Before 2017, the SSTs in CAMS are from a climatology, not varying from year to year. From 2017 onwards, the SSTs from both reanalyses are identical.

Cheers,

Andreas