Level-2 product definition

The CIMR Level-2 SIC, SIC1H, and SIED products are on instrument grid, thus with a (Nscanl,Nscanp) structure. We describe below the main variables for each type of products. Each product file will in addition have geolocation information (latitude and longiture) and attributes, that are not described here at this stage.

Sea Ice Concentration (SIC3H)

Table 1 define the content (TBC) of the Level-2 sea-ice concentration (SIC3H) product files. Their structure is inspired by that of the EUMETSAT OSI SAF and ESA CCI products.

Table 1 NetCDF Group: Processed data (TBC) for SIC3H

name	description	units	dimensions
ice_conc	The main SIC variable, with all filters applied	n/a [0-1]	(Nscanl,Nscanp)
raw_ice_conc_values	“raw” SIC values before the OWF and thresholds are applied	n/a [0-1]	(Nscanl,Nscanp)
total_standard_uncertainty	total uncertainty (1 sigma) of the SIC field	n/a [0-1]	(Nscanl,Nscanp)
algorithm_standard_uncertainty	uncertainty (1 sigma) contribution due to the tie-point variability	n/a [0-1]	(Nscanl,Nscanp)
smearing_standard_uncertainty	uncertainty (1 sigma) contribution due to renapping and pan-sharpening	n/a [0-1]	(Nscanl,Nscanp)
radiometric_standard_uncertainty	uncertainty (1 sigma) contribution due to \(Ne\Delta T\)	n/a [0-1]	(Nscanl,Nscanp)
status_flag	A flag indicating status of retrieval, e.g. “nominal”, “over land”, …	n/a	(Nscanl,Nscanp)

At this stage, it is foreseen that the SIC3H product files can have several SIC estimates, from different channel combinations. Each SIC will have its own group, similar to that in Table 1.

Sea Ice Concentration 1H (SIC1H)

The SIC1H product files will have variables similar to those in Table 1, possibly less of them (e.g. no uncertainty variable) if these have to be skipped for timeliness requirements. By the same token, we expect only one SIC algorithm to run within the NRT1H chain and thus only one SIC group in the data file. Finally, depending on the configuration of the NRT1H chain, selected brightness temperature channels might also be shipped in the SIC1H product file, to help downstream applications within sea-ice navigation safety (e.g. regional sea-ice drift and type monitoring). Candidate microwave channels are Ku (H- and V-pol) and Ka (H- and V-pol).

Table 2 NetCDF Group: Processed data (TBC) for SIC1H

name	description	units	dimensions
ice_conc	The main SIC variable, with all filters applied	n/a [0-1]	(Nscanl,Nscanp)
raw_ice_conc_values	“raw” SIC values before the OWF and thresholds are applied	n/a [0-1]	(Nscanl,Nscanp)
status_flag	A flag indicating status of retrieval, e.g. “nominal”, “over land”, …	n/a	(Nscanl,Nscanp)
brightness_temperature	brightness temperature (NRT1H) for selected channels, remapped at the location of ice_conc	K	(Nband,Nscanl,Nscanp)

Sea Ice Edge (SIED)

Table 1 define the content (TBC) of the Level-2 sea-ice edge (SIED) product files.

Table 3 NetCDF Group: Processed data (TBC) for SIED

name	description	units	dimensions
ice_edge	The main SIED variable: 0 for open water, 1 for sea ice.	n/a	(Nscanl,Nscanp)
probability_correct	Probability (\(P \in [0.5;1]\)) of correct classification	n/a	(Nscanl,Nscanp)
status_flag	A flag indicating status of retrieval, e.g. “nominal”, “over land”, …	n/a	(Nscanl,Nscanp)