Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Ocean Sci., 12, 825-842, 2016
https://doi.org/10.5194/os-12-825-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
27 Jun 2016
Major improvement of altimetry sea level estimations using pressure-derived corrections based on ERA-Interim atmospheric reanalysis
Loren Carrere, Yannice Faugère, and Michaël Ablain Collecte Localisation Satellites, Parc Technologique du Canal, 8–10 rue Hermès, 31520 Ramonville-Saint-Agne, France
Abstract. The new dynamic atmospheric correction (DAC) and dry tropospheric (DT) correction derived from the ERA-Interim meteorological reanalysis have been computed for the 1992–2013 altimeter period. Using these new corrections significantly improves sea level estimations for short temporal signals (< 2 months); the impact is stronger if considering old altimeter missions (ERS-1, ERS-2, and Topex/Poseidon), for which DAC_ERA (DAC derived from ERA-Interim meteorological reanalysis) allows reduction of the along-track altimeter sea surface height (SSH) error by more than 3 cm in the Southern Ocean and in some shallow water regions. The impact of DT_ERA (DT derived from ERA-Interim meteorological reanalysis) is also significant in the southern high latitudes for these missions.

Concerning more recent missions (Jason-1, Jason-2, and Envisat), results are very similar between ERA-Interim and ECMWF-based corrections: on average for the global ocean, the operational DAC becomes slightly better than DAC_ERA only from the year 2006, likely due to the switch of the operational forcing to a higher spatial resolution. At regional scale, both DACs are similar in the deep ocean but DAC_ERA raises the residual crossovers' variance in some shallow water regions, indicating a slight degradation in the most recent years of the study. In the second decade of altimetry, unexpectedly DT_ERA still gives better results compared to the operational DT.

Concerning climate signals, both DAC_ERA and DT_ERA have a low impact on global mean sea level rise (MSL) trends, but they can have a strong impact on long-term regional trends' estimation, up to several millimeters per year locally.


Citation: Carrere, L., Faugère, Y., and Ablain, M.: Major improvement of altimetry sea level estimations using pressure-derived corrections based on ERA-Interim atmospheric reanalysis, Ocean Sci., 12, 825-842, https://doi.org/10.5194/os-12-825-2016, 2016.
Publications Copernicus
Download
Short summary
New dynamic atmospheric (DAC_ERA) and dry tropospheric (DT_ERA) correction have been computed for the altimeter period using the ERA-Interim meteorological reanalysis. The corrections improve sea level estimations in Southern Ocean and in shallow waters; the impact is the most important for the first decade of altimetry, when operational meteorological models had a weaker quality. DT_ERA remains better in the recent period. New corrections significantly impact long-term regional trends.
New dynamic atmospheric (DAC_ERA) and dry tropospheric (DT_ERA) correction have been computed...
Share