**Nota bene:** For the computation of the periodic coefficients, see the note at the bottom of the » Introduction tab » page.

# EIGEN-GRGS.RL03.MEAN-FIELD

EIGEN-GRGS.RL03.MEAN-FIELD is complete to degree and order 260. It is based on EIGEN-6S2 for the part between degree 81 and 260. The time-variable gravity (TVG) coefficients between degrees 1 and 80 are obtained from a regression on the GRGS-RL03-v1 monthly time series (2003-2012). For degree 2 this TVG part is extended to 1985-2012 through the use of a GRGS SLR-only (Lageos+Lageos-2) solution between 1985 and 2003.

Outside of the measurements period (1985-2012 for degree 2, 2003-2012 for degrees 3 to 80), the gravity field is extrapolated with a zero-slope assumption.

The modeling of the TVG part includes, as was the case for EIGEN-6S2:

- Two annual and two semi-annual coefficients
- One bias and one drift for each year. (Note that the reference date of the bias is the beginning of the period of validity of the coefficient, i.e. the beginning of the year in most cases, see format). The bias and drift are in general coherent so that the result is a piece wise linear function, except in the case of earthquakes. Three major earthquakes have been introduced in the modelling: Sumatra on 2004/12/26, Concepcion on 2010/02/27 and Sendai on 2011/03/11.

Download EIGEN-GRGS.RL03.MEAN-FIELD in extended GRACE format / ICGEM-V2 format

# Reference field_for_RL03-v1_grids

The geoid and EWH grids and images are computed by difference of the RL03-v1 solutions to a static reference mean field, which is an arbitrary reference. In the case of the RL03-v1 grids and images, we have used the following reference mean-field : Reference field_for_RL03-v1_grids. This static mean field is close to the actual value of the Earth’s gravity field at the date 2008.0.

# EIGEN-GRGS.RL03-v2.MEAN-FIELD

EIGEN-GRGS.RL03-v2.MEAN-FIELD is complete to degree and order 260. It is based on GOCE-DIR5 for the part between degree 81 and 260. The time-variable gravity (TVG) coefficients between degrees 1 and 80 are obtained from a regression on the GRGS-RL03-v2 monthly time series (2002.5-2014.5). For degree 2 this TVG part is extended to 1985-2014.5 through the use of a GRGS SLR-only (Lageos+Lageos-2) solution between 1985 and 2003.

Outside of the measurements period (1985-2014.5 for degree 2, 2003-2014.5 for degrees 3 to 80), the gravity field is extrapolated with a zero-slope assumption.

The modeling of the TVG part includes for the first time two annual and two semi-annual coefficients for each year, in addition to one bias and one drift for each year:

- One bias and one drift for each year. (Note that the reference date of the bias is the beginning of the period of validity of the coefficient, i.e. the beginning of the year in most cases, see format). The bias and drift are in general coherent so that the result is a piece wise linear function, except in the case of earthquakes. Three major earthquakes have been introduced in the modelling: Sumatra on 2004/12/26, Concepcion on 2010/02/27 and Sendai on 2011/03/11.
- Two annual and two semi-annual coefficients for each year.

This gravity field model has been adopted as **the geopotential model of the GDR-E altimetric standards**.

Download EIGEN-GRGS.RL03-v2.MEAN-FIELD in extended GRACE format / ICGEM-V2 format

# EIGEN-GRGS.RL03-v2.MEAN-FIELD.mean_slope_extrapolation

Identical to EIGEN-GRGS.RL03-v2.MEAN-FIELD, except that the null slope on extrapolation is replaced by the average slope of the signal over the period 2003.0 – 2014.0.

Download EIGEN-GRGS.RL03-v2.MEAN-FIELD.mean_slope_extrapolation in extended GRACE format / ICGEM-V2 format