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cp4cds / cmip6_range_check_old

CMIP6 Data Range Check: extract and evaluate information about range of data values in CMIP6 datasets.
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Amon.rsds : negative values in data from EC-Earth Consortium #47

Open martinjuckes opened 3 years ago

martinjuckes commented 3 years ago

The variable is positive by construction, it is the component of the longwave radiation which is propagating downwards, and measured positive in a downwards direction. Negative values are found in four EC-Earth datasets identified by ESGF id and handles below:

CMIP6.CMIP.EC-Earth-Consortium.EC-Earth3-AerChem.historical.r1i1p1f1.Amon.rlds.gr.v20200624: hdl:21.14100/1820eb8e-15b2-349b-a97b-effd99dd6f60 CMIP6.CMIP.EC-Earth-Consortium.EC-Earth3-Veg-LR.historical.r1i1p1f1.Amon.rlds.gr.v20200217: hdl:21.14100/f9117c34-6764-345d-9c5c-0c5f185b0c4e CMIP6.ScenarioMIP.EC-Earth-Consortium.EC-Earth3.ssp434.r101i1p1f1.Amon.rlds.gr.v20200412: hdl:21.14100/8eb94b78-b44e-3d99-94c1-f715a935c013 CMIP6.ScenarioMIP.EC-Earth-Consortium.EC-Earth3.ssp534-over.r101i1p1f1.Amon.rlds.gr.v20200412: hdl:21.14100/1560865c-a150-3f46-b11c-e8445cff6aa1

Contact: from file: cmip6-data@ec-earth.org ; from citation : -- "van Noije", "noije@knmi.nl" -- Veg: "Klaus Wyser", "klaus.wyser@smhi.se",

klauswyser commented 3 years ago

Thanks for letting us know. I had a quick look at CMIP6.ScenarioMIP.EC-Earth-Consortium.EC-Earth3.ssp534-over.r101i1p1f1.Amon.rlds.gr.v20200412 and can confirm that there is one gridcell in one month with a small negative value (-4.5 W/m2). I'll open an issue on the EC-Earth dev portal for further discussion.

martinjuckes commented 3 years ago

Thanks @klauswyser : there are also lower values. I found a minimum of -60.05 W m-2 in v20200217/rlds_Amon_EC-Earth3-Veg-LR_historical_r1i1p1f1_gr_197801-197812.nc (hdl:21.14100/d58f3895-84dc-4a27-b614-bf3708af9a96).

klauswyser commented 3 years ago

I just happend to have a look at the ssp534-over experiment first. Indeed, the EC-Earth3-Veg-LR_historical is riddled with negative values, I find them every year, and not just one single gridpoint.

klauswyser commented 3 years ago

Sorry that it took so long to come up with an answer, we had to coordinate this across the EC-Earth consortium. There is an error in the radiation output coming from the atmopshere component in EC-Earth. It is not clear whether this is a systematic error or occurs randomly, and how large the impact could be in daily or monthly averages. We concluded that we cannot fix the error easily and therefore just made a note at the es-doc errata server so users at least become aware of the problem.