High resolution dynamic ocean topography in the Southern Ocean from GOCE

Albertella, A.; Savcenko, R; Janjić, Tijana; Rummel, Reiner; Bösch, Wolfgang; Schröter, Jens

doi:10.1111/j.1365-246x.2012.05531.x

Cited by 30 publications

(17 citation statements)

References 33 publications

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“…To extract only the geostrophic component of the drifter data, an estimate of the Ekman component is considered . Furthermore the surface velocities corresponding to the time series of Sea Level Anomalies are taken into account, as described in Albertella et al (2012).…”

Section: Geostrophic Velocitiesmentioning

confidence: 99%

Mean Dynamic Ocean Topography in the Southern Ocean from GRACE and GOCE and Multi-mission Altimeter Data

Albertella¹,

Savcenko²,

Janjić

et al. 2013

International Association of Geodesy Symposia

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The ocean north of the Antarctic continent is one of the most dynamic ocean areas on our globe. It is also critical for the regulation of the global climate. We compute a high resolution mean dynamical ocean topography (MDT) using geodetic data and derive a detailed model of the global ocean circulation in this crucial area. The MDT is determined using multimission altimeter data and the GRACE/GOCE gravity model GOCO2s. The mean sea surface is observed from joint cross-over adjustment of 17 years of satellite altimetry. The two geodetic gravity missions GRACE and GOCE allow the computation of a global geoid with unprecedented accuracy and spatial resolution. While GRACE greatly improved the accuracy and global consistency of gravity models at long to medium wavelengths, GOCE is adding highly accurate geoid information in the medium wavelength range. The geoid and mean sea surface have been made consistent by a spectral filter. The MDT is represented as a spherical harmonic expansion. This allows us to analyze the oceanographic content in different wavelength bands. In order to assess properties of the MDT and of the derived geostrophic velocity field, velocities are compared with independent data from satellite tracked surface drifters in the area of the Antarctic Circumpolar Current (ACC). The RMS of the differences is less than 9 cm/s even if shortest scales (100 km) are considered. Our study shows that, with just 6 months of GOCE data, we are able to improve significantly the geodetic MDT.

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Section: Geostrophic Velocitiesmentioning

confidence: 99%

Mean Dynamic Ocean Topography in the Southern Ocean from GRACE and GOCE and Multi-mission Altimeter Data

Albertella¹,

Savcenko²,

Janjić

et al. 2013

International Association of Geodesy Symposia

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“…Then we translate the grid MSS to the spherical harmonic coefficients (Albertella and Rummel 2009;Feng et al 2013). Since the spatial resolution of MSS is significantly higher than the gravity models, these short-scale features involved in the MDT should be removed by filtering to make sure that the geodetic MDTs are consistent with the spatial resolution of the gravity field.…”

Section: A Errors In Mdtmentioning

confidence: 99%

Errors of Mean Dynamic Topography and Geostrophic Current Estimates in China’s Marginal Seas from GOCE and Satellite Altimetry

Jin

Feng

Andersen

2014

Journal of Atmospheric and Oceanic Technology

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The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and satellite altimetry can provide very detailed and accurate estimates of the mean dynamic topography (MDT) and geostrophic currents in China's marginal seas, such as, the newest high-resolution GOCE gravity field model GO-CONS-GCF-2-TIM-R4 and the new Centre National d'Etudes Spatiales mean sea surface model MSS_CNES_CLS_11 from satellite altimetry. However, errors and uncertainties of MDT and geostrophic current estimates from satellite observations are not generally quantified. In this paper, errors and uncertainties of MDT and geostrophic current estimates from satellite gravimetry and altimetry are investigated and evaluated in China's marginal seas. The cumulative error in MDT from GOCE is reduced from 22.75 to 9.89 cm when compared to the Gravity Recovery and Climate Experiment (GRACE) gravity field model ITG-Grace2010 results in the region. The errors of the geostrophic currents from GRACE are smaller than from GOCE with the truncation degrees 90 and 120. However, when the truncation degree is higher than 150, the GRACE mean errors increase rapidly and become significantly larger than the GOCE results. The geostrophic velocities based on GOCE-TIM4 have higher accuracy and spatial resolution, and the mean error is about 12.6 cm s 21 , which is more consistent with the in situ drifter's results than using GRACE data.

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“…Existing studies regarding dynamic topography and ocean circulation estimates from GOCE [e.g., Knudsen et al, 2011;Bingham et al, 2011;Albertella et al, 2012;Janjić et al, 2012] as well as pre-GOCE studies [e.g., Andersen and Knudsen, 2009;Maximenko et al, 2009;Rio et al, 2011] make use of special filter techniques to homogenize the different information and to combine a gravity field model with altimetric-derived sea surface heights. No or only insufficient information about the variances and especially the covariances are provided with these dynamic topography models.…”

Section: Introductionmentioning

confidence: 99%

Mean dynamic topography estimates purely based on GOCE gravity field models and altimetry

Becker

Brockmann

Schuh

2014

Geophys. Res. Lett.

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Citation:Becker, S., J. M. Brockmann, and W.-D. Schuh (2014), Mean dynamic topography estimates purely based on GOCE gravity field models and altimetry, Geophys. Res. Lett., 41, 2063Lett., 41, -2069Lett., 41, , doi:10.1002 Abstract The quality of mean dynamic topography (MDT) models derived from an altimetric mean sea surface and a gravity field model mainly depends on the spatial resolution and accuracy of the particular gravity field model. We use an integrated approach which allows for estimating the MDT and its (inverse) covariance matrix on a predefined grid which is one of the requirements for ocean data assimilation. The quality and accuracy of the MDT directly reflects the quality and accuracy of the used gravity field model. For the first time, MDT estimates along with its full error covariance matrix based on Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) data can be provided. We demonstrate the progress accomplished with GOCE processing and the valuable contribution of the GOCE gravity field models regarding the estimation of the MDT by showing results based on altimetric observations of Jason-1 and Envisat in combination with different GOCE gravity field models for the North Atlantic.

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High resolution dynamic ocean topography in the Southern Ocean from GOCE

Cited by 30 publications

References 33 publications

Mean Dynamic Ocean Topography in the Southern Ocean from GRACE and GOCE and Multi-mission Altimeter Data

Mean Dynamic Ocean Topography in the Southern Ocean from GRACE and GOCE and Multi-mission Altimeter Data

Errors of Mean Dynamic Topography and Geostrophic Current Estimates in China’s Marginal Seas from GOCE and Satellite Altimetry

Mean dynamic topography estimates purely based on GOCE gravity field models and altimetry

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