[Go-essp-tech] Handling missing data in the CMIP5 archive

[Michael Lautenschlager]

Hi Karl et al.,

yes, I agree that we cannot expect all variables from all models and all 
centres. We have to deal with differing completeness for DOI published 
data entities. This is not a problem for DOI data publication because 
each individual DOI points to the description and to the complete list a 
data which is hind this entity.

But what we should discuss and decide on are the criteria for 
completeness and for the "QC-L2 passed" flag (see Frank's earlier 
response) for accepting data entities in the CMIP5/IPCC-AR5 reference 
data archive and for DOI data publication. This is exactly on of the 
topics I would like to discuss at the ESGF day and during the GO-ESSP 
meeting.

Ag's request rise the question from a theoretical to a practical level 
and we have to agree on a common procedure in order to guarantee 
consistency across archives in QC level assignment and in completeness 
of data entities.

   Best wishes, Michael


Am 28.04.2011 19:38, schrieb Karl Taylor:
> Dear Ag,
>
> There is another possible way of handling the "missing data" issue.  
> I'm not sure that a dataset should be be required to be complete 
> (i.e., required to include all time slices) to be considered eligible 
> for DOI assignment.  That is, we could relax the criteria.  Note that 
> I don't think we require *all* variables requested within a single 
> dataset to be present, so some datasets will indeed be incomplete but 
> be eligible for a DOI.  I think the QC procedure should be to check 
> with the modeling group, and if they can't supply the missing 
> time-slices, then we somehow note this flaw in the dataset 
> documentation and if other QC checks are passed, assign it a DOI.
>
> The criteria for getting a DOI should be that there are no known 
> errors in the data itself, and that there are no major problems with 
> the metadata.  In this case the data will be reliable, and analysts 
> will be welcome to use it and publish results, so I think it should be 
> assigned a DOI.
>
> What do others think?
>
> Best regards,
> Karl
>
>
> On 4/28/11 3:12 AM, ag.stephens at stfc.ac.uk wrote:
>> Dear all,
>>
>> At BADC we have come across our first "missing data" issue in the CMIP5 datasets we are ingesting. We have an example of some missing months for a particular set of variables that was revealed when running the QC code from DKRZ.
>>
>> It would be very useful for the CMIP5 archive managers to make an authoritative statement about how we should handle missing data time steps in the archive.
>>
>> I propose the following response when a Data Node receives a dataset in which time steps are missing:
>>
>>   1. QC manager (i.e. whoever runs the QC code) informs Data Provider that there is missing data in a dataset (specifying full DRS structure and date range missing).
>>
>>   2a. If Data Provider says "no, cannot provide this data" then the affected datasets cannot get a DOI and cannot be part of the "crystallised archive". STOP
>>
>>   2b. Data Provider re-generates files, data is re-ingested, new version is generated, QC is re-run, all is good. STOP
>>
>>   2c. Data Provider cannot re-generate but wants to pass QC - so needs to create the required files full of missing data.
>>
>>   3. Data Provider creates missing data files and sends, data re-ingested, new version is generated, QC re-run, all good. STOP
>>
>> In cases 2a and 2c it would also be very useful if the dataset is annotated to inform the user which dates have been FILLED with missing data. This would, I believe, be in the QC logs but we might want a more prominent record of this if possible.
>>
>> Cheers,
>>
>> Ag
>> BADC--
>> Scanned by iCritical.
>
>
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