Request for new standard name: land_ice_transport_across_line

[mankoff]

Topic for discussion

Name: land_ice_transport_across_line
Units: kg s-1

Description: Similar to sea_water_transport_across_line: Transport across_line means that which crosses a particular line on the Earth's surface; formally this means the integral along the line of the normal component of the transport.

That is, we need a variable for iceberg discharge in Greenland and Antarctica. water_flux_into_sea_water_from_{land_ice,icebergs} is close, but has the wrong units (flux needs m-2) and this new term is for solid ice, not water.

[taylor13]

In descriptions of land_ice, we say:

"Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock and also includes ice-shelves.

So I think iceberg_transport_across_line would be better. Note that "icebergs" is already used in 3 standard names. This would, of course, exclude flow of ice_shelves across the line.

[mankoff]

Agreed that what I suggested should be iceberg_transport_across_line. But then there should also be the term I suggested which has the same units but updated definition: Discharge across the grounding line (or any other line) but remains land_ice after crossing said line, unlike icebergs. The use case here is ice entering (creating) ice shelves on the supply side, rather than ice leaving ice shelves on the calving side.

[mankoff]

More generally, ice_transport_across_line could work in both cases.

[taylor13]

Regarding the second (new) case, if the line followed a coast line, I agree that ice_transport_across_line might work (except we might worry about ice-clouds in the atmosphere mistakenly being included), but if the line were out at sea, then "ice transport" would definitely include sea-ice. If sea ice should be excluded, I think "land_ice_transport ..." would be better in this case, which would include flow from land to sea or flow of ice-shelves when no longer grounded, but it would exclude sea ice and icebergs, I guess.
Anyone else want to weigh in on this?

[JonathanGregory]

I agree that iceberg_transport_across_line and land_ice_transport_across_line would both be suitable as standard names if they are needed. The "lines" referred to by such quantities are geographically defined, whereas the grounding line is a mobile geophysical boundary. Therefore I thnk land_ice_transport_across_grouding_line would also be a reasonable quantity to name.

[efisher008]

Hi all,

Could this be converted into an issue in the vocabularies repository? This would be the preferred route as it is how we usually manage proposals for new standard names. Alternatively, a new issue can be opened with the final proposal once the term name and description have been agreed.

Best regards,
Ellie

[mankoff]

Hi @efisher008,

I wanted to open this as an issue, per the instructions under "How do I propose a change?" at https://github.com/cf-convention/cf-convention.github.io/blob/main/faq.md#how-do-i-propose-a-change . The text and links there are to new issues at https://github.com/cf-convention/discuss/issues but if you try to open an issue there, it pushes you to this discussion forum.

[efisher008]

Hi @mankoff,

I think I see what has happened. The location for submitting CF Standard Name proposals moved in July this year from the cf-convention/discuss repo to the newly created cf-convention/vocabularies repo. This was done to provide a clearly labelled repo which collects together all discussions and resources related to the CF controlled vocabularies (standard names, area types and standardized regions).

The history of this change can be found here:
https://github.com/orgs/cf-convention/discussions/334

And the new repository for vocabularies is here:
https://github.com/cf-convention/vocabularies

It seems as though the page you found still directs to the old discuss repo, which was not caught when changing the links on the website to point to the new vocabularies repo. I will raise a request for this to be changed!

[JonathanGregory]

Sorry, Ken @mankoff. I will update the FAQ. Thanks for discovering this.

[JonathanGregory]

I have opened website issue 553 to update the FAQ.

[efisher008]

Hi Ken @mankoff, Jonathan @JonathanGregory,

Putting aside the website issue Jonathan has now created, would it now be possible to open a formal proposal in the cf-convention/vocabularies repo (by creating a new issue using the CF Standard Names template, process guidance here) as it seems this discussion has reached a consensus on what is needed?

If I understood correctly, the proposal would consist of the following names:
iceberg_transport_across_line
land_ice_transport_across_line
land_ice_transport_across_grouding_line
with descriptions and canonical units (which must be physically consistent with a P06 term in the NERC Vocab Server).

@mankoff I will leave it up to your discretion how to go forward with the proposal.

Best wishes,
Ellie

[JonathanGregory]

I agree with you, Ellie. If Ken @mankoff has time to make the proposal, I think we will agree it easily. A new standard names issue can be opened with this link.

[mankoff]

I've opened cf-convention/vocabularies#235

But I'm not sure I should have - reasons included in that ticket. Closing this as this entire discussion should have been there.