Request to change Sea-ice cover (code 401) to Sea-ice concentration, name, definition and units

[jeffrkey]

Initial request

This request is to change the name, definition, and units of the variable Sea-ice cover (code 401). The current definition of "cover" is the fraction of an ocean area. That is the definition of sea-ice concentration as commonly used by the scientific community. Sea-ice cover, like snow cover, is typically a binary variable, where the area of interest (i.e. a satellite pixel or a model grid cell) is considered to be either snow covered or snow free. Snow fraction is analogous to sea-ice concentration in that it is the fraction of some area covered by snow. We therefore propose a name change and a small change to the definition. While the variable Sea-ice cover could be retained, it's definition should be modified.

Current name: Sea-ice cover
Proposed name: Sea-ice concentration
Current definition: Fraction of an ocean area where ice is present.
Proposed definition: Fraction of an ocean area covered by sea ice.
Current units, Measuring and Uncertainy: %, Horizontal: km, Stability: % (per decade)
Current units, Measuring and Uncertainy: %, Horizontal: m, Stability: % (per decade)

Amendment details

The proposed update of the existing variable is as follows:

notation	name	definition
401	Sea-ice concentration	Fraction of an ocean area covered by sea ice.

All units required already exist and no further change is needed.

Requestor(s)

Group: Global Cryosphere Watch (GCW)
POCs:

Jeff Key ([email protected]), University of Wisconsin
Petra Heil, University of Tasmania and Australian Antarctic Division, [email protected]
Rodica Nitu, WMO, [email protected]

Stakeholder(s)

National and international ice services, e.g., US National Ice Center, North American Ice Service, Norwegian Ice Service; scientific community for remote sensing validation, meteorological/climatological and modeling applications.

Applications or Systems

• OSCAR/Surface
• OSCAR/requirements
• Radar/DB
• OceanOPS
• WHOS
• WDQMS
• GBON Compliance Monitor
• Other

Expected impact of change

LOW

Collaborators

GCW Sea Ice Best Practices team; GCW Cryosphere and Polar Observations (CRYORA) team
Belén Martín Míguez, Ocean Earth System Category (ESAC)

References

To be added

Comments

No response

Publication(s)

Manual on Codes (WMO-No. 306), Volume I.3, WMO Codes Registry - WMDR

To be added

Validation

There are countless publications on the validation of satellite-derived sea ice concentration.

[IARC2000]

Strongly endorsing the proposed change of variable name and definition to:
Proposed name: Sea-ice concentration
and
Proposed definition: Fraction of an ocean area covered by sea ice.

Not in agreement with retaining the current variable name:
"While the variable Sea-ice cover could be retained, it's definition should be modified."
-> Sea-ice cover is qualitative while sea-ice concentration is quantitative.