Sea ice re-tracking estimates - Sentinel-3 Altimetry Technical Guide - Sentinel Online
There is a single re-tracker dedicated to SAR mode sea-ice waveforms. This re-tracker method has its heritage in the empirical-based sea-ice re-tracker implemented in the CryoSat-2 mission. It corresponds to a simplified version of the 5-sections ice-sheet retracker used in CryoSat-2. In this case only three segments are considered: leading edge is modelled as a Gaussian; an exponenetial function is used to fit the trailing edge decaying; and a third order polynomial function.
The main output of these two retrackers annotated in the Level-2 product are:
- corrected "sea-ice" altimeter range
- corrected "sea-ice" backscatter coefficient
- "sea-ice" sea surface height
- "sea-ice" sea surface height anomaly
- interpolated "sea-ice" sea surface height anomaly
- freeboard (difference between the measured surface height and the expected sea-surface height at the given location)
PARAMETER |
Surface Type Classification Derived from Altimeter |
NETCDF NAME |
surf_type_class_[x1]_[x2] |
DESCRIPTION |
The ALT_MAN_WAV_02 algorithm discriminates waveforms assigning a surface type classification based upon the record contents. The possible surface types are: open ocean (0b), sea_ice (1b), lead (2b) and unclassified (3b). |
UNITS |
|
DATA SET AVAILABILITY |
Reduced: none |
OPERATING MODE AVAILABILITY |
SAR |
DATA ORIGIN |
1 Hz Ku/C-bands: none |
ADDITIONAL INFORMATION |
None |
PARAMETERS RELATED |
None |
PARAMETER DETAILED DESCRIPTION |
ESA's Global Land and Ocean Mission for GMES Operational Services |
PARAMETER |
Corrected Sea-Ice Backscatter Coefficient |
NETCDF NAME |
sig0_sea_ice_sheet_[x1]_[x2] |
DESCRIPTION |
SAR mode: sea-ice retracking. |
UNITS |
10-2 dB |
DATA SET AVAILABILITY |
Reduced: none |
OPERATING MODE AVAILABILITY |
SAR |
DATA ORIGIN |
1 Hz Ku/C-bands: none |
ADDITIONAL INFORMATION |
None |
PARAMETERS RELATED |
None |
PARAMETER DETAILED DESCRIPTION |
ESA's Global Land and Ocean Mission for GMES Operational Services |
PARAMETER |
Corrected Sea-Ice Altimeter Range |
NETCDF NAME |
range_sea_ice_[x1]_[x2] |
DESCRIPTION |
SAR mode: sea-ice re-tracking using the ALT_RET_ICE_03 algorithm. |
UNITS |
10-4 m. An offset of 700 000 m to be added to the value read from the netCDF file. |
DATA SET AVAILABILITY |
Reduced: None |
OPERATING MODE AVAILABILITY |
SAR |
DATA ORIGIN |
1 Hz Ku/C-bands: none |
ADDITIONAL INFORMATION |
None |
PARAMETERS RELATED |
None |
PARAMETER DETAILED DESCRIPTION |
ESA's Global Land and Ocean Mission for GMES Operational Services |
PARAMETER |
Sea-Ice Sea Surface Height and Sea-Ice Sea Surface Height Anomaly |
NETCDF NAME |
sea_ice_sea_surf_[x1]_[x2] |
DESCRIPTION |
SAR mode: sea-ice re-tracking using the ALT_RET_ICE_03 algorithm. |
UNITS |
10-4 m |
DATA SET AVAILABILITY |
Reduced: none |
OPERATING MODE AVAILABILITY |
SAR |
DATA ORIGIN |
1 Hz Ku/C-bands: none |
ADDITIONAL INFORMATION |
None |
PARAMETERS RELATED |
Interpolated Sea-Ice Sea Surface Height Anomaly: int_sea_ice_sea_ssha_[x1]_[x2] |
PARAMETER DETAILED DESCRIPTION |
ESA's Global Land and Ocean Mission for GMES Operational Services |