[Go-essp-tech] Fwd: Expected number of variables for which quality control will be needed

[Bentley, Philip]

Hi Martin,

It's good to hear that our initial tranche of CMIP5 data 'appears' to
get the green light. Since we produced the data using the latest (at the
time) release of CMOR-2 I think, as a project, we'd be in deep doo-doos
if it hadn't passed :-)

As regards the 4 QC checks you mention below, the first three would
appear to be fairly cheap operations. However, I'm aware from my own
recent experience of checking our data outputs that computing the
min/max bounds for a given atomic dataset (one variable spread over
numerous netcdf files) is a cpu- and time-expensive operation.

So I was curious to know why this particular check needs to be done?
Since most of the min/max bounds have been removed from the MIP tables,
what bounds would be used in the QC L2 checks? Perhaps it's the case
that this check is simply skipped if no min/max bounds are defined in
the MIP tables?

Regards,
Phil

> 
> I hope we can get some conclusion on what constitutes passed 
> QC L2 before the Asheville meeting -- we have some UKMO data 
> which appears to pass all the tests -- but it is hard to be 
> sure because of the complexity of the output from the quality 
> control code. We would like to declare this data as passed, 
> so that we can get onto the next problem (replicating it to 
> other centres).
> 
> The quality control document (attached) lists 4 objective 
> tests under QC level 2:
> (1) Number of records in each file consistent with metadata
> (2) Regular time steps
> (3) Metadata consistent with data request
> (4) Minimum and maximum checked against specified ranges (or 
> a default based on the mean).
> 
> An email from Martina this morning implied that subjective 
> tests would only come in at the QC L3 stage or if there is 
> some doubt about the objective tests. 
> 
> I'm not clear why the process is so complex when the document 
> only specifies a small number of objective tests -- though 
> there clearly is complexity of the workflow (ensuring that 
> results for tests of all files are recorded and retrievable). 
> 
> Regards,
> Martin
> 
>