I've been looking at ice/snow land/sea area types too.
I have a microwave algorithm that together with a DEM separates the world into four mutually exclusive categories:
- land with ice or snow
- land without ice or snow
- lake/sea with ice or snow
- lake/sea without ice or snow
I'm currently planning to use:
"ice_and_snow_on_land"
"land"
"lake_ice_or_sea_ice"
"sea" or "ice_free_sea"
"ice_and_snow_on_land" is perfect.
I'd like to replace "land" with something like "land_without_snow_or_ice". The closest choices are "bare_ground", "snow_free_land", and "ice_free_land". I assume "bare_ground" means no vegetation, not no frozen water, so I'm avoiding it. (There's no help text.)
I guess "lake_ice_or_sea_ice" is OK. I'd like it better if it explicitly included snow, but probably the assumption is that snow that's on lake/sea and not over ice will melt immediately?
If there is no need to mention snow for water surfaces then "ice_free_sea" is pretty good. But it's odd there's no option for "ice_free_lake" or "ice_free_lake_or_sea".
-- Evan
?On 10/4/18, 1:29 PM, "Taylor, Karl E." <taylor13 at llnl.gov> 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
Received on Fri Oct 12 2018 - 04:36:56 BST
