Improved Sea Surface Height from Satellite Altimetry in Coastal Zones: A Case Study in Southern Patagonia

LAGO, LORELEY; SARACENO, MARTÍN; RUIZ ETCHEVERRY, L.; PASSARO, MARCELO; OREIRO, FERNANDA; DONOFRIO, ENRIQUE; GONZÁLEZ, RAÚL

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

IEEE Geoscience & Remote Sensing Society

Lugar: Mississipi; Año: 2017

1939-1404

High resolution 20-Hz Jason-2 satellitealtimetry data obtained from crossing tracks numbered 52 and 189 in San MatiasGulf, Argentina, are compared with a 22-month-longtime series of sea levelmeasured by a bottom pressure recorder. It was deployed 1.3km from the nominalintersection of the two tracks and 0.9km from the coast. Results show that byimproving retracking and tidal modeling, satellite altimetry data become moreaccurate close to the coast. Indeed, a larger number of reliable data areobtained up to 1.6km from the coast when satellite data are retracked usingALES (Adaptive Leading Edge Subwaveform retracker) rather than using theclassic Brown model. The tidal model that showed the lowest root sum square ofthe difference (RSS) between the in situ and the modelled tidalamplitude and phase is TPXO8 (RSS 4.8cm). Yet, the lowest differencefrom in situ tidal constituents is obtained by harmonic analysis of theavailable 23-year-long 1-Hz altimetry data set (RSS 4.1cm), highlightingthe potential of altimetry data to compute tides. Considering ALES retrackingand TPXO8 tidal correction for the 20-Hz Jason-2 data, we finally show that itis possible to retrieve 70% more data and to improve correlation with in situmeasurements from 0.79 to 0.95. The sea level anomaly obtained this way has aroot mean square difference (RMSD) from in situ data of only 13cm asclose as 4km from the coast. Overall, the analysis performed indicatessatellite altimetry data can be greatly improved, even in complex macrotidalcoastal regions.