A comparison of the annual cycle of sea level in coastal areas from gridded satellite altimetry and tide gauges.

Published in Continental Shelf Research, v. 92:87-97
Authors

Ruiz-Etcheverry, L.A., Saraceno, M., Piola, A.R., Valladeau, G. and Möller, O.O.
Publication year 2014
DOI https://doi.org/10.1016/j.csr.2014.10.006
Affiliations
  • Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina
  • Centro de Investigación del Mar y la Atmósfera, Buenos Aires, Argentina
  • Instituto Franco Argentino para el estudio del clima y sus impactos (UMI-IFAECI), Argentina
  • Departamento Oceanografía, Servicio de Hidrografía Naval, Argentina
  • Collecte Localisation Satellites (CLS), Toulouse, France
  • Instituto de Oceanografia, Universidade de Federal do Rio Grande, Rio Grande, Brazil

 
IAI Program

CRN3
IAI Project CRN3070
Keywords
Annual cycle
Altimetry
Coastal area
Tide gauges
Sea level anomaly

Highlights

•Validation of gridded altimetry data at annual scales in coastal areas.

•The annual cycle is well represented by the altimeter for 76.4% of the cases.

•Regions where RMSD are larger than 4 cm are related with oceanographic processes.

•Annual cycle in the Southwestern Atlantic coast is well represented by altimetry data.

Abstract

In this work we compare the annual component of sea level variations derived from 478 worldwide-distributed tide gauges with the annual component computed from a weekly gridded multi-mission altimeter product. Gridded altimetry data products allow for spatio-temporal analyses that are not possible based on along-track altimetry data. However, a precise validation is necessary in the coastal region before the gridded data can be used. Results of the comparisons show that root-mean-square differences (RMSD) between the two datasets are &le2 cm for 76.4% of the sites. RMSD higher than 4 cm are caused by narrow coastal currents, nearby river outflows or other local phenomena. A methodology is proposed to assess the accuracy of the seasonal component of the gridded altimeter product in regions with a low density net of tide gauges. As a case study it is shown that the Southwestern Atlantic coast is a suitable region to study the spatio-temporal variability of the annual cycle of sea level since RMSD between annual altimetry data and in-situ data are lower than 2.1 cm.