Abstract's details

Assessment of Sentinel 6 altimeter data along the Northwest Atlantic shelf

Hui Feng (University of New Hampshire, United States)


Doug Vandemark (University of New Hampshire, United States); Alejandro Egido (NOAA – Laboratory for Satellite Altimetry, United States)

Event: 2022 Ocean Surface Topography Science Team Meeting

Session: Sentinel-6 Validation Team (S6VT) feedbacks

Presentation type: Type Forum only

A Sentinel-6 mission goal is to maintain data quality closer to the coastline than products from previous conventional altimeter missions such as T/P and Jason-1,2,3. This requires making use of new High Resolution mode (HRM) or SAR mode data to improve the performance in coastal areas, following on from pioneering data from the Sentinel-3 (S3) and Cryosat missions.
This project will build upon ongoing assessments of S3 SAR altimeter data along the US east coast and Nova Scotian Shelf (SS) to examine tandem-phase S-6 and Jason 3 measurements with a specific focus near to the coast. We have already observed clearly measurable improvements using S-3 HR data when compared to Low Resolution Mode (LRM) data. This new S6 Cal/Val work will utilize similar analysis and metrics to evaluate key GDR products including range (i.e. SSH/SSHA), SWH, and Sigma0 (i.e. wind speed). The overall goal is to provide an assessment of S6 altimeter products along the US northeast and SS shelf, with specific objectives being 1) to analyze S6 and Jason-3 data quality ( SSH/SSHA, SWH, and Sig0 ), 2) to quantify noise and bias in key S6 variables via inter-comparison of LRM and HRM (SARM) in reference to J3 LRM data, 3) to assess the accuracy of the altimeter SSH and SSH-derived geostrophic estimates, across the shelves and coastal zones, and 4) to explore coastal applications using S6 HRM data to better identify coastal currents.
As one potential application, a recent study (Feng et al., 2016) showed that interior Gulf of Maine (GoM) subsurface salinity variability was closely tied to change in southwestern Scotian Shelf (SS) inflow derived from SSHA measured by TOPEX/Jason-1, 2 LRM altimeter data. We will revisit this idea that altimetry-based alongshelf geostrophic flow anomalies derived from repeat tracks in J3/S6 and other nearby passes from S- 3 and SARAL/AltiKa along the Southwest SS can serve as a proxy for remote Gulf of Maine forcing. Specifically, we seek to predict water mass change (e.g. salinity ) inside the GoM. We will quantify potential improvements gained using HRM SSHA-based currents in comparison with LRM data. In the future, we intend to routinely generate along-shelf current products using along track data from multiple altimeters on the southwest Scotian Shelf and we will investigate the shortest feasible time scales resolved using the suite of satellites.
Hui Feng
University of New Hampshire
United States