CMEMS Arctic MFC: Validation of GLO-NEMO sea ice concentration
Multi-model approach
Here, we present validation results from CMEMS global ocean circulation model, in order to provide product quality information that is supplementary to the results from CMEMS-ARC. Processing and computation of metrics are performed identically to the implementation for the ARC product, from which validation results are presented from this page (lower table of dates).
Documentation
These web pages contain an outline of the validation algorithm. Download this document for a detailed description of the algorithm, the observations that are used etc. Note that model results are interpolated onto the observational grid prior to computation of validation metrics.
The implementation of a set of sea ice classes follows the ice class definitions used for the Ice chart product SEAICE_ARC_SEAICE_L4_NRT_OBSERVATIONS_011_002. Thus, the sea ice classes correspond to the following sea ice concentrations from the ice chart product (discrete values with an interval of 0.1):
- Open Water (OW): 0.0
- Very Open Drift Ice (VODI): 0.1, 0.2, 0.3
- Open Drift Ice (ODI): 0.4, 0.5, 0.6
- Close Drift Ice (CDI): 0.7, 0.8
- Very Close Drift Ice (VCDI): 0.9, 1.0
- Fast Ice (FI): 1.0
In addition, regions with no ice is defined as a separate class Ice Free (IF). Note that the model does not distunguish between classes VCDI and "Fast Ice", so these two classes are also merged into one class in the validation, which will be referred to as Very Close Drift Ice. Note also that for the observational products, classes IF and VCDI have been split according to the distance from the MIZ.
Validation results: N. hemisphere OSI SAF sea ice concentration
Validation data: N. hemisphere OSI SAF sea ice concentration
Validation of the CMEMS Arctic MFC results for sea ice concentrations described above is supplemented by a validation using the data provided to CMEMS by OSI SAF as the observational reference. This product has a much coarser horizontal resolution than the ice charts, and the model results are not independent of these data. However, in contrast to ice charts, the OSI SAF products covers the entire region with ice infested waters in the northern hemisphere, so results from this validation provide information about the model performance in regions not covered by ice charts.
OSI SAF sea ice concentrations based on SSMIS data are available as aggregated ice concentrations (from CMEMS product SEAICE_GLO_SEAICE_L4_NRT_OBSERVATIONS_011_001).
NEMO
The model results are produced with the NEMO
assimilative ocean model system (CMEMS product
GLOBAL_ANALYSIS_FORECAST_PHY_001_024 from 2016-10-27,
and the now deprecated GLOBAL_ANALYSIS_FORECAST_PHYS_001_002 for validations before 2016-10-27).
Presently, NEMO assimilates data for sea surface temperature, sea level anomalies, temperature
and salinity profiles, and sea ice concentration.
The ocean circulation model product is
developed and maintained by Mercator Ocean.
NEMO results are freely available for registered CMEMS users on marine.copernicus.eu.