Sea Ice Edge (OSI-402-c) and Sea Ice Type (OSI-403-c)
In the context of the first Continuous Development and Operation Phase (CDOP-1), the near-real-time products of sea ice edge and sea ice type were introduced in the Ocean and Sea Ice SAF product's portofolio and has since then continouosly been upgraded by improving the algorithm and by including more sensors. Today, it is based on the low resolution passive microwave instruments of SSMIS and AMSR-2, and the scatterometer ASCAT.
The products of edge and type are gridded datasets. They are provided on a Polar Stereographic Grid where the grid-point spacing is 10 km similar to the one used for the other OSI SAF sea ice products. Note, that due to the ongoing upgrades, the archive data of the products are not to be used as consistent data records.
1. Introduction and FAQ
How should I cite this dataset?
The edge dataset shall be referred to as the Sea ice edge product of the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF, https://osi-saf.eumetsat.int).
The type dataset shall be referred to as the Sea ice type product of the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF, https://osi-saf.eumesat.int).
Which satellite sensors are processed?
The sensors and channels used for these products are SSMIS (19h, 19v, 37v, 91h, 91v) on board DMSP platform F18, AMSR-2 (19h, 19v, 37v, 89h, 89v) on board JAXA platform GCOM-W1, and ASCAT (C-band backscatter) on board EUMETSAT platform Metop-A and Metop-B.
What is the spatial grid resolution of this product?
The products of sea ice edge and type are gridded datasets. The grid resolution has 10 km spacing on a Polar Stereographic projection mapping. Definitions for the projection parameters can be found in the NetCDF files as well as in the Product User's Manual.
What is the time-span of this product?
One day (24 hours).
What is the difference between sea ice edge and sea ice type products?
Both the sea ice edge product and the sea ice type product are classification products differing between different ice classes. Sea ice edge differs between the classes open water, open ice, and closed ice which are defined from the ice concentration thresholds of 30% and 70%, respectively. Sea ice type differs between first-year ice and multiyear ice which are defined from target regions of known ice types and uses the sea ice edge product to define the boarder between sea ice and open water.
How is the boarder between sea ice and open water defined in the OSI SAF sea ice edge and type products?
All the sea ice classes (open ice, closed ice, first-year ice, and multiyear ice) correspond to sea ice concentrations above 30%. And open water corresponds to less than 30% ice coverage.
Today's product file is empty, what happened?
Two possible answers:
- Missing input data: In case of interrupted data link with the satellite operating centres, no input swath data are available for processing of the sea ice data, resulting in an empty grid.
- Ambiguous data: Due to atmospheric noise and surface melting, it is not possible to do ice type classification during the melt season with the sensors/channels we process. Empty product files are distributed from 16th of May to 30th September in the NH grid for not interrupting the data flow to operational centres. For the SH grid, at present to ice type classification has been developed.
In both cases, the status_flag dataset in the product file indicates the reasons for missing data.
What is the legend used for the quicklooks?
Quicklooks for both products can be viewed from this page (NH, SH).
Colour codes
| Colour | Sea Ice Edge | |
|---|---|---|
| land | Operational Sea Ice Edge product | |
| open water | ... | |
| open ice | ... | |
| closed ice | ... | |
| unclassified (coastal areas) | ... | |
| Colour | Sea Ice Type | |
| land | Operational Sea Ice Type product | |
| open water | ... | |
| first-year ice | ... | |
| multiyear ice | ... | |
| ambiguous. | ... | |
| unclassified (coastal areas) | ... | |
Do you have a similar ice type product for Antarctic regions?
No. At present ice type classification has not been defined in the OSI SAF algorithms.
I do not fancy NetCDF, do you have other formats?
The processing chain is currently producing GRIB and HDF in addition to NetCDF files. However, both GRIB and HDF will be faced out in near future. NetCDF will stay. Please let us know (contact) if you need another format.
2. Algorithms
3. Validation
Validation of the OSI SAF sea ice products can be found in the product specific validation report, also referred to in Documentation and links.
4. Documentation and links
The following documentation is available, further describing the operational products of OSI-402 sea ice edge and OSI-403 sea ice type.
Quicklooks for both products can be accessed from these pages: (NH, SH).
Data can be accessed from FTP:
- sea ice edge Near-Real-Time (last 31 days), Archive (since 2005)
- sea ice type Near-Real-Time (last 31 days), Archive (since 2005)
5. References
5.1 Peer-reviewed articles
| [1] | Breivik, L.-A., S. Eastwood and T. Lavergne (2012), Use of C-Band Scatterometer for Sea Ice Edge Identification. Geoscience and Remote Sensing, IEEE Transactions, vol.50, no.7, pp.2669-2677. |
