Abstract's details
Benefits of multi-altimeter combination for Arctic sea surface height retrievals
CoAuthors
Event: 2022 Ocean Surface Topography Science Team Meeting
Session: Science II: Large Scale Ocean Circulation Variability and Change
Presentation type: Type Oral
Contribution: PDF file
Abstract:
We present a new Arctic sea level dataset (https://doi.org/10.24400/527896/a01-2020.001) based on the optimal interpolation of three satellite radar altimetry missions.
A dedicated processing is applied on measurements from SARAL/AltiKa, CryoSat-2 and Sentinel-3A to identify radar echoes coming from leads in the ice covered regions of the Arctic Ocean. After a data editing and application of instrumental, environmental and geophysical corrections tailored for the Arctic Ocean, these echoes are combined with open ocean echoes through an optimal interpolation scheme to map sea surface anomalies. The resulting gridded sea level anomaly fields provide an unprecedented resolution for this type of products:
the final gridded fields cover all latitudes north of 50°N, on a 25 km EASE2 grid, with one grid every three days over four years from July 2016 to June 2020.
We benefit from the use of an adaptive retracker on SARAL/AltiKa. This retracking algorithm is able to process both specular (leads) and brownian (open ocean) echoes with one phyisical model. Using this retracker on SARAL/AltiKa removes the need to estimate an empirical bias between open ocean an ice covered areas. Therefore SARAL/AltiKa measurements provide a consistent baseline for the cross-calibation of CryoSat-2 and Sentinel-3A, for which leads are retracked using an empirical algorithm (TFMRA).
When compared to independent tide gauge data available in the basin, the combined product exhibits a much better performance and temporal resolution than any of our single mission dataset. This dataset has already been used to document new Atlantic water pathways north of Svalbard (https://doi.org/10.1029/2020JC016825).
Processing details and validation results are documented in Prandi et al., 2021 (https://doi.org/10.5194/essd-2021-123).
This product, supported by CNES, is a prototype for the future generation of regional Arctic CMEMS-SLTAC products that will generate both gridded sea level anomaly fields and cross calibrated along track products for data assimilation.
Future evolutions of this regional Arctic Ocean product will benefit from the inclusion of upcoming satellite radar altimetry missions such Sentinel-3 C&D, and CRISTAL.
A dedicated processing is applied on measurements from SARAL/AltiKa, CryoSat-2 and Sentinel-3A to identify radar echoes coming from leads in the ice covered regions of the Arctic Ocean. After a data editing and application of instrumental, environmental and geophysical corrections tailored for the Arctic Ocean, these echoes are combined with open ocean echoes through an optimal interpolation scheme to map sea surface anomalies. The resulting gridded sea level anomaly fields provide an unprecedented resolution for this type of products:
the final gridded fields cover all latitudes north of 50°N, on a 25 km EASE2 grid, with one grid every three days over four years from July 2016 to June 2020.
We benefit from the use of an adaptive retracker on SARAL/AltiKa. This retracking algorithm is able to process both specular (leads) and brownian (open ocean) echoes with one phyisical model. Using this retracker on SARAL/AltiKa removes the need to estimate an empirical bias between open ocean an ice covered areas. Therefore SARAL/AltiKa measurements provide a consistent baseline for the cross-calibation of CryoSat-2 and Sentinel-3A, for which leads are retracked using an empirical algorithm (TFMRA).
When compared to independent tide gauge data available in the basin, the combined product exhibits a much better performance and temporal resolution than any of our single mission dataset. This dataset has already been used to document new Atlantic water pathways north of Svalbard (https://doi.org/10.1029/2020JC016825).
Processing details and validation results are documented in Prandi et al., 2021 (https://doi.org/10.5194/essd-2021-123).
This product, supported by CNES, is a prototype for the future generation of regional Arctic CMEMS-SLTAC products that will generate both gridded sea level anomaly fields and cross calibrated along track products for data assimilation.
Future evolutions of this regional Arctic Ocean product will benefit from the inclusion of upcoming satellite radar altimetry missions such Sentinel-3 C&D, and CRISTAL.