Altimetry observations in coastal regions: A case study in the Gulf of Maine
Hui Feng1, Doug Vandemark1, and Remoko. Scharroo2, John Wilkin3 and Guoqi Han4
1
Ocean Process Analysis Laboratory, University of New Hampshire, USA.
39 College Road Durham, NH 02824, U.S.A. E-mail: hui.feng@unh.edu
2
Altimetrics, LLC, Cornish, NH 03745, USA
3
Rutgers University, USA
4
Fisheris and Oceans, Canada
Altimetry success in understanding sea surface height SSH signatures and their gradients (i.e. geostropic
currents) in the basin and meso-scales over the open oceans has been widely recognized. Once an altimeter
approaches the coastline, however, the quality of SSHA measurements becomes questionable due to numerous
causes including 1) corrupted radiometer and altimeter measurements due to land contamination within their antenna
footprints, 2) inaccurate and missing geophysical correction terms, 3) improper sampling schemes and etc. In the
recent decade, significant progress in processing coastal altimetry data has been made in many coastal settings, such
as the North-Black seas (Madsen et al., 2007), the northwest European shelf (Volkov et al., 2007), the
Mediterranean Sea (Vignudelli et al., 2005; Bouffard et al., 2008; Lebedev etal., 2008), and the US west coast
(Saraceno et al., 2008). Specific processing approaches have been proposed to improve the altimeter data quality in
coastal regions.
Taking advantage of these appearing progresses, we have been developing a reprocessing
methodology for deriving altimeter SSHA data with improved quality and maximized data recovery in the Gulf of
Maine and Mid-Atlantic Bight (GoM-MAB) region dedicated to its coastal applications.
The objectives of this work is 1) to demonstrate our methodology (e.g. the new editing, missing-correction
recovery and filtering) of reprocessing the along-track SSHA of the altimeters topex, Jason-1 and Jason-2; 2) to
show how to evaluate various de-aliasing corrections objectively and to choose one with the best performance in the
coastal region, and 3) to validate the SSHA and the along-track SSHA-estimated across-track surface geostrophic
velocity anomalies in comparison with in situ coastal observations (i.e. coastal tide gauge and buoy-based currents
and winds). This oral presentation will focus on #3).
1