Hi Karl,
I am responding to your question about ice_sheet/land_ice (CF-metadata Digest, Message 2, Vol 186, Issue11), and deleted the other topics from the thread.
?ice_sheet would be the Greenland and Antarctic ice sheets. It contains both the grounded_ice_sheet (part of the ice sheet flowing over bedrock, and you are technically right that an ice sheet is a combination of many many glaciers) and floating_ice_shelf (the part that only flows on water).
land_ice is much bigger as it includes the polar ice sheets, glaciers in non-polar regions (glaciers are considered small body of ice: for example in the Alps, or the US), and the small ice caps. The ice caps are also a large combinations of glaciers, but too small to be considered an ice sheets. For example the Svartissen Ice Cap in northern Norway.
For ISMIP6, we are interested in ice_sheet, but some climate models may also include glaciers and ice caps (which ISMIP6 does not care about). Hence the use of both ice_sheet and land_ice in the ISMIP6 protocol (and I cant recall if land_ice was already present in CMIP5, but I think that it was).
I don?t know the origin of ice_on_land.
Jonathan: please help me make my answers less confusing...
I hope that this helps,
Sophie
Message: 2
Date: Tue, 9 Oct 2018 17:19:36 +0000
From: "Taylor, Karl E." <taylor13 at llnl.gov>
To: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
Subject: Re: [CF-metadata] ice_sheet / land_ice confusion
Message-ID: <ec366da6-0f45-0c3a-0ebe-d7b20f7cfb55 at llnl.gov>
Content-Type: text/plain; charset="utf-8"
HI all,
Can anyone provide any guidance on the difference between ice_sheet and
land_ice (see below)?? It has a bearing on metadata to be stored with
CMIP6 model output.
thanks and best regards,
Karl
On 10/4/18 10:29 AM, Taylor, Karl E. wrote:
> Hi all,
>
> I think there might be a mistake in the descriptions of "ice_sheet"
> and/or "land_ice" in the "area type" table at
> http://cfconventions.org/Data/area-type-table/current/build/area-type-table.html
> .
>
> I find there the following definitions:
>
> ice_sheet: An area type of "ice sheet" indicates where ice sheets are
> present. It includes both grounded ice sheets resting over bedrock and
> ice shelves flowing over the ocean, but excludes ice-caps and glaciers
> (in contrast to land_ice, which includes all components).
>
> land_ice: "Land ice" means glaciers, ice-caps, grounded ice sheets
> resting on bedrock and floating ice-shelves.
>
> ice_on_land: The area type "ice_on_land" means ice in glaciers, ice
> caps, grounded ice sheets (grounded and floating shelves), river and
> lake ice, and any other ice on a land surface, such as frozen flood
> water. This is distinct from the area type 'land ice' which has a
> narrower definition.
>
> Are "ice-caps" and "glaciers" really excluded from "ice_sheet".? I would
> have thought that "ice-cap" would be an ice_sheet located over a pole
> (or something to that effect).? And i thought ice_sheets were just big
> glaciers.
>
> ice_on_land is pretty clearly any frozen water, except sea ice,
> icebergs, and ice particles in clouds, that is exposed to the atmosphere.
>
> So, I guess I'm trying to understand the difference between ice_sheet
> and land_ice, and why do we need both of these?
>
> thanks and best regards,
> Karl
End of CF-metadata Digest, Vol 186, Issue 11
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Received on Tue Oct 09 2018 - 12:03:33 BST
