Time-variable gravity fields (RL02)

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Spherical harmonic coefficients of 10-day gravity field models

These are 10-day gravity field models from SH degree 2 up to SH degree and order 50, given every 10 days, using GRACE and LAGEOS data (in ITRF2000).

Models are provided every 10 days and are based solely on the 10 days (maximum) of data that are in this time interval (whereas "version 1" models were provided every 10 days but were based on three consecutive 10-day periods with the weighting 0.5/1./0.5).

10-day models are stabilized towards EIGEN-GRGS.RL02.MEAN-FIELD, more precisely towards the realization of EIGEN-GRGS.RL02.MEAN-FIELD at each given epoch, with a new constraint law that depends on the degree and on the order of each coefficient (in version 1, the law was only degree-dependent and the models were constrained towards the static part of EIGEN-GL04S and later EIGEN-GL04C).

It is reminded to the users of the GRGS products that NO SMOOTHING OR FILTERING is necessary when using them, since they have already been stabilized during their generation process.

Missing solutions

There are some gaps in this time series, coming either from GPS, from accelerometers or from KBR data gaps. Fourteen 10-day solutions are missing:

Grids, images and movies

Grids, images and movies of geoid and equivalent water heights differences with static field are provided. The grids are 1° x 1° global grids of geoid height or equivalent water heights differences (in meters) between time-variable solutions and static field(at reference date if the static field includes time-variable terms). The images represent geoid or equivalent water heights differences (in millimeters) between time-variable solutions and static field (at reference date if the static field includes time-variable terms). Images are compiled in geoid or EWH movies.

Dealiasing products

The files provided here contain the so-called "dealiasing products" used by CNES/GRGS, temporally averaged in a manner consistent with the way the time-variable gravity field models are produced. In the processing of the GRACE data, the gravitational influence of the Earth atmospheric pressure on the satellites' orbits, as well as the oceanic response to it, is taken into account in the form of ECMWF 3-D atmospheric pressure fields over the whole Earth every 6 hours (with linear interpolation in-between) and MOG2D model of the response of the oceanic domain to the atmospheric forcing (pressure and wind) at the same temporal resolution. A conversion from Pascal to normalized gravitational potential units is performed.

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Formats

• SH models (GRGS format): GINS format
• Grids: Grids format
• Dates (calendar dates, day of year, julian day 1950): Dates format

Download archive files (.tar.gz)

Latests gravity fields: November 14th 2008 to April 22nd 2009!

Grids in GRACE format will be available soon (links are uneffective yet).

♦ Watch the movies : Movie Geoid / Movie Water

Statistics

♦ Number of days included in the 10-day models : See #days

♦ EWH grids mean, standard-deviation and RMS over the oceans : See signal over oceans (m)

Download individual files

© CNES/GRGS 2009 | Website NOVELTIS