The new CNES-CLS18 global mean dynamic topography
Open Access
- 17 June 2021
- journal article
- research article
- Published by Copernicus GmbH in Ocean Science
- Vol. 17 (3), 789-808
- https://doi.org/10.5194/os-17-789-2021
Abstract
The mean dynamic topography (MDT) is a key reference surface for altimetry. It is needed for the calculation of the ocean absolute dynamic topography, and under the geostrophic approximation, the estimation of surface currents. CNES-CLS mean dynamic topography (MDT) solutions are calculated by merging information from altimeter data, GRACE, and GOCE gravity field and oceanographic in situ measurements (drifting buoy velocities, hydrological profiles). The objective of this paper is to present the newly updated CNES-CLS18 MDT. The main improvement compared to the previous CNES-CLS13 solution is the use of updated input datasets: the GOCO05S geoid model is used based on the complete GOCE mission (November 2009–October 2013) and 10.5 years of GRACE data, together with all drifting buoy velocities (SVP-type and Argo floats) and hydrological profiles (CORA database) available from 1993 to 2017 (instead of 1993–2012). The new solution also benefits from improved data processing (in particular a new wind-driven current model has been developed to extract the geostrophic component from the buoy velocities) and methodology (in particular the computation of the medium-scale GOCE-based MDT first guess has been revised). An evaluation of the new solution compared to the previous version and to other existing MDT solutions show significant improvements in both strong currents and coastal areas.Keywords
This publication has 37 references indexed in Scilit:
- Integration of HF Radar Observations for an Enhanced Coastal Mean Dynamic TopographyFrontiers in Marine Science, 2020
- Twenty-five years of Mercator ocean reanalysis GLORYS12 at Drake Passage: Velocity assessment and total volume transportAdvances in Space Research, 2019
- Evaluation of GlobCurrent surface ocean current products: A case study in AustraliaRemote Sensing of Environment, 2018
- ESA's satellite‐only gravity field model via the direct approach based on all GOCE dataGeophysical Research Letters, 2014
- The CORA dataset: validation and diagnostics of in-situ ocean temperature and salinity measurementsOcean Science, 2013
- The ERA‐Interim reanalysis: configuration and performance of the data assimilation systemQuarterly Journal of the Royal Meteorological Society, 2011
- Observation and Estimation of Lagrangian, Stokes, and Eulerian Currents Induced by Wind and Waves at the Sea SurfaceJournal of Physical Oceanography, 2009
- Calculating the Ocean’s Mean Dynamic Topography from a Mean Sea Surface and a GeoidJournal of Atmospheric and Oceanic Technology, 2008
- Direct measurements of ocean surface velocity from space: Interpretation and validationJournal of Geophysical Research: Oceans, 2005
- Mixed layer depth over the global ocean: An examination of profile data and a profile‐based climatologyJournal of Geophysical Research: Oceans, 2004