Analyses of altimetry errors using Argo and GRACE data
This study presents the evaluation of the performances of satellite altimeter missions by comparing the altimeter sea surface heights with in situ dynamic heights derived from vertical temperature and salinity profiles measured by Argo floats. The two objectives of this approach are the detection of...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-05-01
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| Series: | Ocean Science |
| Online Access: | http://www.ocean-sci.net/12/647/2016/os-12-647-2016.pdf |
| _version_ | 1818877500785164288 |
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| author | J.-F. Legeais P. Prandi S. Guinehut |
| author_facet | J.-F. Legeais P. Prandi S. Guinehut |
| author_sort | J.-F. Legeais |
| collection | DOAJ |
| description | This study presents the evaluation of the
performances of satellite altimeter missions by comparing the altimeter sea
surface heights with in situ dynamic heights derived from vertical
temperature and salinity profiles measured by Argo floats. The two objectives
of this approach are the detection of altimeter drift and the estimation of
the impact of new altimeter standards that requires an independent reference.
This external assessment method contributes to altimeter calibration–validation analyses
that cover a wide range of activities. Among them, several examples are given
to illustrate the usefulness of this approach, separating the analyses of the
long-term evolution of the mean sea level and its variability, at global and
regional scales and results obtained via relative and absolute comparisons.
The latter requires the use of the ocean mass contribution to the sea level
derived from Gravity Recovery and Climate Experiment (GRACE) measurements. Our analyses cover the estimation of the
global mean sea level trend, the validation of multi-missions altimeter
products as well as the assessment of orbit solutions.<br><br>Even if this approach contributes to the altimeter quality assessment, the
differences between two versions of altimeter standards are getting smaller
and smaller and it is thus more difficult to detect their impact. It is
therefore essential to characterize the errors of the method, which is
illustrated with the results of sensitivity analyses to different
parameters. This includes the format of the altimeter data, the method of
collocation, the temporal reference period and the processing of the ocean
mass solutions from GRACE. We also assess the impact of the temporal and
spatial sampling of Argo floats, the choice of the reference depth of the
in situ profiles and the importance of the deep steric contribution. These
analyses provide an estimation of the robustness of the method and the
characterization of associated errors. The results also allow us to draw
some recommendations to the Argo community regarding the maintenance of the
in situ network. |
| first_indexed | 2024-12-19T13:59:17Z |
| format | Article |
| id | doaj.art-73c18f891cf3464a8e8ec04d1c86d12c |
| institution | Directory Open Access Journal |
| issn | 1812-0784 1812-0792 |
| language | English |
| last_indexed | 2024-12-19T13:59:17Z |
| publishDate | 2016-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Ocean Science |
| spelling | doaj.art-73c18f891cf3464a8e8ec04d1c86d12c2022-12-21T20:18:30ZengCopernicus PublicationsOcean Science1812-07841812-07922016-05-0112364766210.5194/os-12-647-2016Analyses of altimetry errors using Argo and GRACE dataJ.-F. Legeais0P. Prandi1S. Guinehut2Collecte Localisation Satellites, Parc Technologique du canal, 8–10 rue Hermès, 31520 Ramonville Saint-Agne, FranceCollecte Localisation Satellites, Parc Technologique du canal, 8–10 rue Hermès, 31520 Ramonville Saint-Agne, FranceCollecte Localisation Satellites, Parc Technologique du canal, 8–10 rue Hermès, 31520 Ramonville Saint-Agne, FranceThis study presents the evaluation of the performances of satellite altimeter missions by comparing the altimeter sea surface heights with in situ dynamic heights derived from vertical temperature and salinity profiles measured by Argo floats. The two objectives of this approach are the detection of altimeter drift and the estimation of the impact of new altimeter standards that requires an independent reference. This external assessment method contributes to altimeter calibration–validation analyses that cover a wide range of activities. Among them, several examples are given to illustrate the usefulness of this approach, separating the analyses of the long-term evolution of the mean sea level and its variability, at global and regional scales and results obtained via relative and absolute comparisons. The latter requires the use of the ocean mass contribution to the sea level derived from Gravity Recovery and Climate Experiment (GRACE) measurements. Our analyses cover the estimation of the global mean sea level trend, the validation of multi-missions altimeter products as well as the assessment of orbit solutions.<br><br>Even if this approach contributes to the altimeter quality assessment, the differences between two versions of altimeter standards are getting smaller and smaller and it is thus more difficult to detect their impact. It is therefore essential to characterize the errors of the method, which is illustrated with the results of sensitivity analyses to different parameters. This includes the format of the altimeter data, the method of collocation, the temporal reference period and the processing of the ocean mass solutions from GRACE. We also assess the impact of the temporal and spatial sampling of Argo floats, the choice of the reference depth of the in situ profiles and the importance of the deep steric contribution. These analyses provide an estimation of the robustness of the method and the characterization of associated errors. The results also allow us to draw some recommendations to the Argo community regarding the maintenance of the in situ network.http://www.ocean-sci.net/12/647/2016/os-12-647-2016.pdf |
| spellingShingle | J.-F. Legeais P. Prandi S. Guinehut Analyses of altimetry errors using Argo and GRACE data Ocean Science |
| title | Analyses of altimetry errors using Argo and GRACE data |
| title_full | Analyses of altimetry errors using Argo and GRACE data |
| title_fullStr | Analyses of altimetry errors using Argo and GRACE data |
| title_full_unstemmed | Analyses of altimetry errors using Argo and GRACE data |
| title_short | Analyses of altimetry errors using Argo and GRACE data |
| title_sort | analyses of altimetry errors using argo and grace data |
| url | http://www.ocean-sci.net/12/647/2016/os-12-647-2016.pdf |
| work_keys_str_mv | AT jflegeais analysesofaltimetryerrorsusingargoandgracedata AT pprandi analysesofaltimetryerrorsusingargoandgracedata AT sguinehut analysesofaltimetryerrorsusingargoandgracedata |