Standard names: *Include aggregated monthly wet-day frequency and monthly wet-day mean precipitation*

[brasmus]

Before submitting an issue be sure you have read and understood the rules for vocabulary changes and review the guidance for constructing standard names These are additions to the standard list and for aggregated data on monthly/seasonal and annual time scales.

Please note that it is fine to group together a number of proposals in a single GitHub issue (i.e. it is not necessary to open a separate issue for each vocabulary term). Change proposals should include the following information as applicable.

Rasmus Benestad This information will be used to add entries to the vocabulary editor: http://cfeditor.ceda.ac.uk/proposals/1. If you prefer not to add your name, your github id will be used instead.

2024-09-09 Also used in the vocabulary editor.

For each term please try to give the following:

- Term f_tp.gt.Xmm

- Description Wet-day frequency - fraction of days in the month with more than X mm in total precipitation

- Units Fraction

- Term mean_tp.gt.Xmm

- Description Wet-day mean precipitation - also known as mean intensity and is the mean precipitation over the days in the month with more than X mm in total precipitation.

- Units mm/day

[github-actions[bot]]

Thank you for your proposal. These terms will be added to the cfeditor (http://cfeditor.ceda.ac.uk/proposals/1) shortly. Your proposal will then be reviewed and commented on by the community and Standard Names moderator.

[github-actions[bot]]

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Standard name moderators are also reminded to review @feggleton @japamment @efisher008

[taylor13]

I think we should be able to apply the term "wet day frequency" to any time-period, not limited to a month. The time interval could be indicated by specifying bounds on the time dimension. So, for example, if we wanted to report the annual wet day frequency for a series of years, the time bounds would be specified as being the start and end of each year.

The standard_name could be patterned after: fraction_of_time_with_sea_ice_area_fraction_above_threshold. I suggest fraction_of_days_with_precipitation_amount_above_threshold.

In the description, we would include "The precipitation amount threshold value must be specified by supplying a coordinate variable or scalar coordinate variable with the standard name of precipitation_amount."

Another option for the standard name: fraction_of_days_with_lwe_thickness_of_precipitation_amount_above_threshold

[efisher008]

Dear Rasmus @brasmus,

Thank you for your proposal. Karl @taylor13 has suggested the name fraction_of_days_with_precipitation_amount_above_threshold or fraction_of_days_with_lwe_thickness_of_precipitation_amount_above_threshold for your proposed term f_tp.gt.Xmm. Following this pattern, the term mean_tp.gt.Xmm could become mean_precipitation_amount_above_threshold with the time bounds specified to a monthly interval, unless there is an example of a use case for handling this separately within CF @taylor13?

Best regards, Ellie

[brasmus]

Thanks. This looks like a good solution. Rasmus

mobil: +47-41122662

On Fri, Nov 1, 2024 at 5:29 PM Ellie Fisher @.***> wrote:

Dear Rasmus @brasmus https://github.com/brasmus,

Thank you for your proposal. Karl @taylor13 https://github.com/taylor13 has suggested the name fraction_of_days_with_precipitation_amount_above_threshold or fraction_of_days_with_lwe_thickness_of_precipitation_amount_above_threshold for your proposed term f_tp.gt.Xmm. Following this pattern, the term mean_tp.gt.Xmm could become mean_precipitation_amount_above_threshold with the time bounds specified to a monthly interval, unless there is an example of a use case for handling this separately within CF @taylor13 https://github.com/taylor13?

Best regards, Ellie

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[larsbarring]

I just saw this discussion. There is already the standard name number_of_days_with_lwe_thickness_of_precipitation_amount_above_threshold

Based on this I have a couple of comments

• I think that the threshold you are using is based is based on "lwe" ( liquid water equivalent), so that should go into the name.
• Personally, when I read "fraction of days" I am thinking of "parts of days" (i.e. something subdaily). Would the contruct proportion_of_days_with_lwe_precipitation.... be better? (I know there already are a number of other standard names using "fraction_of_days").
• Also, note that there is an old discussion on "non-strict" comparisons in #31. It seems that there were convergence (although I have not reviewed it in detail again) towards distinguishing between strict and non-strict comparisons. That discussion was partly related other discussions and lost steam, but when now introducing a new standard name I suggest that it would relevant take on board the distinction between ..._above_... (>) and ..._at_or_above_... (≥). It is not clear which one it is from the original proposal here, but I know that often "wet days" is defined as "days having at least 1 mm/day" (i.e. _at_or_above_)