Minimize Quality Information
Data editing

Sentinel-3 SRAL/MWR products include a number of parameters which provides information about the quality and characteristics of these products.

Sentinel-3 SRAL/MWR products parameters could be available at two data rates: 1Hz (1 measurement per second) and 20Hz (20 measurements per second). Some of the parameters are available at 1Hz only, at 20 Hz only or at both data rates.

 

Sentinel-3 Altimetry toolbox ( http://www.altimetry.info/toolbox/ ) provides a sub-set of pre-defined formulas for editing Sea Surface Height and Sea Level Anomaly formulas for different missions. Figure 1 shows the case of Sentinel-3.

Figure 1: Sentinel-3 data editing using S3 Altimetry toolbox

 

Sentinel-3 parameters are filled with a default value when these parameters have not been able to be computed. This default value is defined for each parameter in the "FillValue" field. Users could use several criteria to filter or discard these parameters value when they are set to default value.

 

Flags

Surface type flag (surf_type_[x1]_[x2]), surface classification flag (surf_class_[x1]_[x2])  and readiometer-derived surface type (rad_surf_type_[x1]_[x2]) prodive information about the surface type of the measurement (open_ocean, semin-enclosed-seas, land, continental_water, aquatic_vegetation,  continental_ice, snow, floating_ice, salted_basin…). These flags could be used to filter the type of surface of the area of interest.

 

Distance to the coast parameter (dist_coast_[x1]_[x2]) could be used to filter measurements close to the coast ( coastal applications).

 

« Ocean » altimeter range validity flag (range_ocean_qual_[x1]_[x2]) indicates the use of not of the 20-Hz estimate of the "ocean" altimeter range when computing 1Hz estimate. « Ocean » backscatter coefficient validity flag (sig0_ocean_qual_[x1]_[x2]) indicates the use of not of the 20-Hz estimate of the "ocean" backscatter coefficient when computing 1Hz estimate.« Ocean » significant waveheight validity flag (swh_ocean_qual_[x1]_[x2]]) indicates the use of not of the 20-Hz estimate of the "ocean" significant waveheight when computing 1Hz estimate.

 

Rain flag (rain_flag_[x1]_[x2]) provides information about the probability of rain. This flag can be used to filter data with or without rain.

Ocean/Sea-ice flag (open_sea_ice_flag_[x1]_[x2]) could be used to filter different types of sea-ice measurements (e.g. first_year_sea_ice, wet_ice, multi_year_sea_ice, ambiguous_mixture_of_type…).

Mean sea surface interpolation flags (interp_flag_mss_sol1_[x1]_[x2] and interp_flag_mss_sol2_[x1]_[x2]) indicate if the interpolation of the mean sea surface solution is " good or bad". These flags could be used to filter "good or bad" interpolated measurements.

Mean dynamic topography interpolation flag (interp_flag_mdt_[x1]_[x2]) indicates if the interpolation of the mean dynamic topography solution is " good or bad". This flag could be used to filter "good or bad" interpolated measurements.

 


PARAMETER

Waveforms Peakiness

NETCDF NAME

peakiness_1_[x1]_[x2]
peakiness_2_[x1]_[x2]
[x1]: 1 Hz or 20 Hz data rates
[x2]: Ku-band or C-band

DESCRIPTION

The ALT_MAN_QUA_03 algorithm computes peakiness 1 similar to the ENVISAT mission.
The ALT_MAN_WAV_01 algorithm computes peakiness 2 similar to the ERS-1 mission.

UNITS

10-3 counts

DATA SET AVAILABILITY

Reduced: none
Standard: 20 Hz Ku/C band
Enhanced: 20 Hz Ku/C band

OPERATING MODE AVAILABILITY

LRM (peakiness 1 only) and SAR (peakiness 2 only)

DATA ORIGIN

1 Hz Ku/C-bands: none
20 Hz Ku-band: ALT_MAN_QUA_03 and ALT_MAN_WAV_01 algorithms
20 Hz C-band: ALT_MAN_QUA_03 and ALT_MAN_WAV_01 algorithms

ADDITIONAL INFORMATION

None

PARAMETERS RELATED

None

PARAMETER DETAILED DESCRIPTION

ESA's Global Land and Ocean Mission for GMES Operational Services

Table 1. Waveforms

 
 

PARAMETER

Interpolation flags

NETCDF NAME

interp_flag_mss_[x1]_[x2]
interp_flag_mdt_[x1]_[x2]
interp_flag_ocean_tide_sol1_[x1]_[x2]
interp_flag_ocean_tide_sol2_[x1]_[x2]
rad_along_track_avg_flag_[x1]_[x2]
[x1]: 1 Hz or 20 Hz data rates
[x2]: Ku-band or C-band

DESCRIPTION

Mean sea surface interpolation flag can be set to:
* good (0b)
* bad (1b).
Mean dynamic interpolation flag can be set to:
* good (0b)
* bad (1b).
Geocentric ocean tide height (GOT) flag can be set to:
* good (0b)
* bad (1b).
Geocentric ocean tide height (FES) flag can be set to:
* good (0b)
* bad (1b).
Radiometer along-track averaging flag
* good (0b)
* fail (1b)

UNITS

None

DATA SET AVAILABILITY

Reduced: none
Standard: 1 Hz and 20 Hz Ku band (MSS only)
Enhanced: 1 Hz 1 Hz and 20 Hz Ku band (MSS only)

OPERATING MODE AVAILABILITY

LRM and SAR

DATA ORIGIN

1 Hz Ku/C-bands: GEN_ENV_MSS_01, GEN_ENV_MDT_01, GEN_ENV_TID_04, GEN_ENV_TID_03 and RAD_MAN_INT_03 algorithms.
20 Hz Ku-band: GEN_ENV_MSS_01 algorithm
20 Hz C-band: none

ADDITIONAL INFORMATION

None

PARAMETERS RELATED

None

PARAMETER DETAILED DESCRIPTION

ESA's Global Land and Ocean Mission for GMES Operational Services

Table 2. Interpolation flags


 

PARAMETER

Geophysical flags

NETCDF NAME

meteo_map_avail_[x1]_[x2]
rain_flag_[x1]_[x2]
open_sea_ice_flag_[x1]_[x2]
[x1]: 1 Hz or 20 Hz data rates
[x2]: Ku-band or C-band

DESCRIPTION

Meteorological map availability can be set to:
* 2 maps nominal (0b)
* 1 map extrapolated (1b)
* no map (2b).
Rain flag can be set to:
* no rain (0b)
* rain (1b)
* high rain probability from altimeter (2b)
* high probability of no rain from altimeter (3b)
* ambiguous situation possibility of ice (4b)
* evaluation not possible (5b).
Ocean/Sea-ice flag can be set to:
* ocean (0b)
* first year sea ice(1b)
* wet ice (2b)
* multi year sea ice (3b)
* ambiguous mixture of type (4b)
* not evaluated (5b)

UNITS

None

DATA SET AVAILABILITY

Reduced: 1 Hz
Standard: 1 Hz
Enhanced: 1 Hz

OPERATING MODE AVAILABILITY

LRM and SAR

DATA ORIGIN

1 Hz Ku/C-bands: GEN_MAN_MET_01, ALT_PHY_GEN_02, GEN_ENV_SUR_02 and GEN_ENV_SUR_03 algorithms
20 Hz Ku-band: none
20 Hz C-band: none

ADDITIONAL INFORMATION

None

PARAMETERS RELATED

open_water_class_[x1]_[x2]
first_year_ice_class_[x1]_[x2]
multi_year_ice_class_[x1]_[x2]
wet_ice_class_[x1]_[x2]
ice_sheet_snow_facies_flag_[x1]_[x2]

PARAMETER DETAILED DESCRIPTION

ESA's Global Land and Ocean Mission for GMES Operational Services

Table 3. Geophysical flags