Question about day of year climatology statistics

[huaracheguarache]

I want to store climatological variables in a netCDF file that are calculated on a day-of-year basis for two different reference periods (1981-2010 and 1991-2020). All of the years in the data have been converted to leap years, and February 29th values have been interpolated where these are missing. I then take the subset of the data that is within the given reference period, and I group it based on the day of year and calculate the climatological variables. One example of such a variable is the median. The result is 366 values for each day of year of the given reference period.

I've been trying to look at chapter 7.4. Climatological Statistics in the CF conventions to see whether it's possible to use the cell_methods and climatology_bounds defined there to store this data, but I'm not sure my data fits into what's specified there.

From what I understand, the standard only permits the following cell_methods:

• time: method1 within years time: method2 over years
• time: method1 within days time: method2 over days
• time: method1 within days time: method2 over days time: method3 over years

Do any of these methods cover my use case? I don't think any of these cover things that are calculated on a day-of-year basis?

cc @TomLav

[davidhassell]

Hello @huaracheguarache,

I have written a response to your question, but I thought it would be nice try this out in the new Discussions forum, which is the new area for this sort of CF discussion. If you could copy and paste your question to over there, yours will be the inaugural question, and I shall answer it :)

Discussions are accessible through the "Discussions" tab at the top of this page (that takes you to https://github.com/orgs/cf-convention/discussions). Once there, all you have to do is select the Q&A about using CF category on the left hand side and create a new discussion into which you can copy what you write here.

Thanks for bearing with me!
David

[huaracheguarache]

No worries! Done.