Global High Resolution Mean Sea Surface Based on ERS-1 35- and 168- Day Cycles and Topex Data

1996 ◽  
pp. 208-217 ◽  
Author(s):  
Michael Anzenhofer ◽  
Thomas Gruber ◽  
Matthias Rentsch
Keyword(s):  
High Resolution ◽  
Sea Surface ◽  
Mean Sea Surface

High‐resolution, high‐accuracy altimeter derived mean sea surface in the Norwegian Sea

1990 ◽  
Vol 14 (1) ◽  
pp. 57-76 ◽  
Author(s):  
Frédérique Blanc ◽  
Sabine Houry ◽  
Pierre Mazzega ◽  
Jean François Minster
Keyword(s):  
High Resolution ◽  
High Accuracy ◽  
Sea Surface ◽  
Norwegian Sea ◽  
Mean Sea Surface

High-resolution numerical modelling of the altimetry-derived gravity disturbances and disturbing gradients

2020 ◽  
Author(s):  
Róbert Čunderlík ◽  
Marek Macák ◽  
Michal Kollár ◽  
Karol Mikula
Keyword(s):  
High Resolution ◽  
Numerical Solution ◽  
Finite Volume ◽  
Sea Surface ◽  
Computational Domain ◽  
Disturbing Potential ◽  
Gravity Disturbances ◽  
Mean Sea Surface ◽  
Upper Boundary ◽  
Goce Satellite

<p>Recent high-resolution mean sea surface models obtained from satellite altimetry in a combination with the GRACE/GOCE-based global geopotential models provide valuable information for detailed modelling of the altimetry-derived gravity data. Our approach is based on a numerical solution of the altimetry-gravimetry boundary-value problem using the finite volume method (FVM). FVM discretizes the 3D computational domain between an ellipsoidal approximation of the Earth's surface and an upper boundary chosen at a mean altitude of the GOCE satellite orbits. A parallel implementation of the finite volume numerical scheme and large-scale parallel computations on clusters with distributed memory allow to get a high-resolution numerical solution in the whole 3D computational domain. Our numerical experiment presents the altimetry-derived gravity disturbances and disturbing gradients determined with the high-resolution 1 x 1 arc min at two altitude levels; on the reference ellipsoid and at the altitude of 10 km above the ellipsoid. As input data, the Dirichlet boundary conditions over oceans/seas are considered in the form of the disturbing potential. It is obtained from the geopotential evaluated on the DTU18 mean sea surface model from the GO_CONS_GCF_2_TIM_R5 geopotential model and then filtered using the nonlinear diffusion filtering. On the upper boundary, the FVM solution is fixed to the disturbing potential generated from the GO_CONS_GCF_2_DIR_R5 model while exploiting information from the GRACE and GOCE satellite missions.</p>

scholarly journals High-resolution mean sea surface computed with altimeter data of Ers-1 (geodetic mission) and topex-poseidon

1996 ◽  
Vol 125 (3) ◽  
pp. 696-704 ◽  
Author(s):  
A. Cazenave ◽  
P. Schaeffer ◽  
M. Berge ◽  
C. Brossier ◽  
K. Dominh ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Surface ◽  
Altimeter Data ◽  
Mean Sea Surface

scholarly journals The Unique Role of the Jason Geodetic Missions for high Resolution Gravity Field and Mean Sea Surface Modelling

2021 ◽  
Vol 13 (4) ◽  
pp. 646
Author(s):  
Ole Baltazar Andersen ◽  
Shengjun Zhang ◽  
David T. Sandwell ◽  
Gérald Dibarboure ◽  
Walter H. F. Smith ◽  
...  
Keyword(s):  
High Resolution ◽  
Gravity Field ◽  
Orbital Plane ◽  
Sea Surface ◽  
Gravity Models ◽  
Life Phase ◽  
Mean Sea Surface ◽  
Successful Launch ◽  
Gravity Recovery ◽  
First Time

The resolutions of current global altimetric gravity models and mean sea surface models are around 12 km wavelength resolving 6 km features, and for many years it has been difficult to improve the resolution further in a systematic way. For both Jason 1 and 2, a Geodetic Mission (GM) has been carried out as a part of the Extension-of-Life phase. The GM for Jason-1 lasted 406 days. The GM for Jason-2 was planned to provide ground-tracks with a systematic spacing of 4 km after 2 years and potentially 2 km after 4 years. Unfortunately, the satellite ceased operation in October 2019 after 2 years of Geodetic Mission but still provided a fantastic dataset for high resolution gravity recovery. We highlight the improvement to the gravity field which has been derived from the 2 years GM. When an Extension-of-Life phase is conducted, the satellite instruments will be old. Particularly Jason-2 suffered from several safe-holds and instrument outages during the GM. This leads to systematic gaps in the data-coverage and degrades the quality of the derived gravity field. For the first time, the Jason-2 GM was “rewound” to mitigate the effect of the outages, and we evaluate the effect of “mission rewind” on gravity. With the recent successful launch of Sentinel-6 Michael Freilich (S6-MF, formerly Jason CS), we investigate the possibility creating an altimetric dataset with 2 km track spacing as this would lead to fundamental increase in the spatial resolution of global altimetric gravity fields. We investigate the effect of bisecting the ground-tracks of existing GM to create a mesh with twice the resolution rather than starting all over with a new GM. The idea explores the unique opportunity to inject Jason-3 GM into the same orbital plane as used for Jason-2 GM but bisecting the existing Jason-2 tracks. This way, the already 2-years Jason-2 GM could be used to create a 2 km grid after only 2 years of Jason-3 GM, rather than starting all over with a new GM for Jason-3.

scholarly journals Matchup Characteristics of Sea Surface Salinity Using a High-Resolution Ocean Model

2021 ◽  
Vol 13 (15) ◽  
pp. 2995
Author(s):  
Frederick M. Bingham ◽  
Severine Fournier ◽  
Susannah Brodnitz ◽  
Karly Ulfsax ◽  
Hong Zhang
Keyword(s):  
High Resolution ◽  
Time Window ◽  
Single Point ◽  
Ocean Model ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Salinity ◽  
Argo Floats ◽  
Statistical Measures ◽  
Salinity Difference

Sea surface salinity (SSS) satellite measurements are validated using in situ observations usually made by surfacing Argo floats. Validation statistics are computed using matched values of SSS from satellites and floats. This study explores how the matchup process is done using a high-resolution numerical ocean model, the MITgcm. One year of model output is sampled as if the Aquarius and Soil Moisture Active Passive (SMAP) satellites flew over it and Argo floats popped up into it. Statistical measures of mismatch between satellite and float are computed, RMS difference (RMSD) and bias. The bias is small, less than 0.002 in absolute value, but negative with float values being greater than satellites. RMSD is computed using an “all salinity difference” method that averages level 2 satellite observations within a given time and space window for comparison with Argo floats. RMSD values range from 0.08 to 0.18 depending on the space–time window and the satellite. This range gives an estimate of the representation error inherent in comparing single point Argo floats to area-average satellite values. The study has implications for future SSS satellite missions and the need to specify how errors are computed to gauge the total accuracy of retrieved SSS values.

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