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Standard names: *Invert Barometer : Ocean surface elevation due to atmospheric pressure* #38
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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. |
Hi Aurore, I have added the name to the editor, you can view it here: I will wait for others to comment on this proposed name. As a starting point I would suggest adding the following phrase for sea surface height: "Sea surface height" is a time-varying quantity.". Best regards, |
Hi Aurore, Just a note that I think it will be worth keeping track of the discussion relating to the use of Best wishes, |
Hi Ellie, What do you think ? |
Dear Aurore @abiardeau Please could you explain what you mean by "amplitude" in this proposed standard name and the two similar ones (#287 #41)? Thanks Jonathan |
Dear @JonathanGregory |
I still have a conceptual difficulty in understanding these proposals, because "sea surface height above height" is the level of a geophysical surface. It's not really "due to" something, like (for instance) the altitude of the tropopause and the density of sea water aren't due to something. The sea surface height, the tropopause and sea water density are always present. "Due to" is used to describe processes, changes and transient phenomena, not states. You must mean the change in SSH, I think, but with respect to what? When this quantity is zero, at what level is the SSH? It's not the geoid, I think, because atmosphere pressure variations are not the reason that SSH departs from the geoid. |
Hi Jonathan, I'm working with Aurore on the production of this new data. If I understand correctly, the current name of the variable might suggest that the “due to” is related to the reference height “the geoid”. But this is not the case. The “due to invert barometer” refers to the variable itself. In fact, it's the contribution of the inverse barometer to the sea surface heigh (the atmospheric pressure that presses on the ocean in the case of a high pressure system, for example, and causes water levels to drop). Is “sea_surface_height_due_to_inverse_barometer_above_geoid” better? I'm am not sure that a reference level is necessary. This field is more about something missing to our ocean model system than can be added afterwards. If this contribution is 0, the total sea level remains unchanged. Please tell me if that answer your question. Best regards, |
Unfortunately this morning I wrote the comment below in #47 instead of here by mistake, and misled Stéphane @slawchune and Karl @taylor13 into replying there as well. Sorry about that! I'm copying the messages here, where they belong. At 0837 UTC on 31st May, I wroteDear Stéphane @slawchune Thanks for your explanation. That clarifies what you mean for me i.e. the IB correction itself, not the corrected SSH. In that case, as you say, a reference level is not needed. We have two existing standard names
On the pattern of these, I think the quantity you mean would be named Would you and others find Best wishes Jonathan At 1003 UTC, @slawchune wrote:Hi Jonathan, thank you very much with your help with this ! I would prefer "sea_surface_height_correction_due_to_air_pressure" because it stays general. "sea_surface_height_increase_due_to_air_pressure_decrease" gives the idea that only low pressure system are considered. actually we compute the inverted barometer at a 1h frequency. So do you think it would make sense to use "sea_surface_height_correction_due_to_air_pressure_and_wind_at_high_frequency" Cheers, At 1435 UTC, @taylor13 wrote:On the small point of "change" vs. "rise" for sea level, I think we should be explicit as to the sign, so "rise" would be better. Similarly, we should find a way to word "sea_surface_height_correction_due_to_air_pressure_and_wind_at_high_frequency" to make it also unambiguous. I agree with Jonathan, that "correction" is vague (and possibly inappropriate), and that we need to specify what is considered "positive" vs. "negative". And "high frequency" depends entirely on context, which leaves it open to misinterpretation. The frequency should be evident from the time coordinate attached to the variable, so I would leave the "frequency part" off. Perhaps "adjustment" rather than "correction" might somehow be incorporated? |
Dear Stéphane @slawchune and Karl @taylor13 The phrase "at high frequency" sounds vague to me, as it does to Karl, but the definition of As a separate matter, like Karl, I think we ought to work out better standard names for these quantities, for two reasons:
Best wishes Jonathan |
Hi Jonathan, sorry it took me a while to reply.
Does this make sense to you? Best wishes |
Dear Stéphane I agree with you that it is not necessary to specify the timescale in the definition or the standard name. You're right, I was assuming the opposite sign i.e. a positive number, meaning SSH is lower than average, if the air pressure anomaly is positive, meaning higher than average. Should we make it Best wishes Jonathan |
Hi Jonathan; I think It's perfect ;) Does it work for @efisher008 and @taylor13 ? Cheers ! |
Oh good, I'm glad that sounds right. Meanwhile, I was working on #37, which made me think of another version of this one, namely |
As an outsider, I can only add that the new versions including "air_pressure" are much easier to understand! Many thanks @JonathanGregory |
Regarding Jonathan's suggestion If both changes had an implied sign, then I think the resulting quantity would be invariably negative. Perhaps we can go with Jonathan's suggested standard name, but in the definition make it clear that the result is expected to be positive when the change in air pressure is negative and negative when the change in air pressure is negative. Or perhaps, I'm just needlessly confused. |
Dear Karl Earlier I suggested specifying the sign of both quantities with constructions like Best wishes Jonathan |
Thanks for the further explanation. An explicit statement in the definition would certainly be sufficient to satisfy me. Thanks. |
OK, thanks, Karl. My preference is for |
I've changed my mind again, back to |
Hi Jonathan, I think we can go with "change_in_sea_surface_height_due_to_change_in_air_pressure" if it helps generalize this quantitiy :) I think it avoid also to think too much about the inversion sign relationship between air pressure and the sea surface height response. |
Dear Stéphane, I have changed the name to the agreed suggestion, and also removed the phrase describing "invert barometer" as this was not referenced in the name. The proposal can be viewed in the editor here: https://cfeditor.ceda.ac.uk/proposal/5277/edit Would you like your name to be added to the author for these proposals along with Aurore (https://github.com/cf-convention/discuss/issues/285, #38, #40, #41, and #49), as you have had significant input on them? Best regards, |
This name was accepted as |
This has been published in v86 of the Standard Names Table (released 5 September 2024). |
Hello,
I am Aurore BIARDEAU from Mercator Ocean international, working for Copernicus Marine service.
Date : 07-03-2024
We are in the process of implementing a new variable in the Copernicus Marine service, and we would be happy to have your feedback on our proposal :
standard_name :
sea_surface_height_amplitude_due_to_invert_barometer
unit : m
definition : The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Invert barometer" means variations in air pressure that give rise to corresponding variations in sea surface topography.
The definition is inspired by the definition of the standard_name
sea_surface_height_correction_due_to_air_pressure_at_low_frequency
, which corresponds to the IB correction in level 2 altimetry data.I can provide more information from my expert colleagues if needed,
Kind regards,
Aurore
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