Can fully-focused or unfocused SAR delay doppler altimeter range data provide enhanced detection of coastal currents?
Event: 2018 Ocean Surface Topography Science Team Meeting
Session: Instrument Processing: Measurement and Retracking
Presentation type: Type Poster
Contribution: PDF file
This study seeks to evaluate the potential of delay doppler altimetry to improve detection of nearshore currents that are common and critical advective pathways within narrow shelf-sea systems. The region of interest here is the Scotian Shelf and, in particular, the coastally trapped Nova Scotia current (NSC). The outer edge of this current resides between 25-50 km from the coast and past efforts using conventional altimeter data have failed to adequately capture expected NSC dynamics. As baseline satellite altimeter data, the study will make use of new high-rate (5-20 Hz) datasets retracked specifically for this region using low resolution mode Cryosat-2, AltiKa, and Jason-2 measurements. These data come from a joint CLS, Environment Canada and Department of Fisheries and Oceans Canada project. Range data will be used to compute sea level anomalies and alongshore geostrophic currents on the Scotian shelf for comparison with along track range data produced using fully-focused and unfocused SAR processing of Cryosat-2 and Sentinel 3 datasets. Past and ongoing in situ hydrographic and current measurement data in the region will be used to provide expected mean and dynamical circulation features from the shelf break up to the coast. Issues under evaluation include improved data recovery nearer to the coast, reduced range noise at scales inside of 20km, differences in SWH and wind estimates, and possible identification of fine-scale signals like internal waves in the FF-SAR data.