Improved determination of the very low-degree Earth’s gravity coefficients for satellite altimetry

Alexandre Couhert (CNES, France)

CoAuthors

Flavien Mercier (CNES, France); Richard Biancale (CNES, France); Christian Bizouard (Observatoire de Paris, SYRTE, France)

Event: 2018 Ocean Surface Topography Science Team Meeting

Session: Precision Orbit Determination

Presentation type: Type Oral

Surprisingly, the low-degree gravity field coefficients, associated with the largest-scale mass redistribution in the Earth’s fluid envelope (atmosphere, oceans and continental hydrology), are the most poorly determined. In particular, the three first-degree geopotential terms are important, as they relate to intrinsic Earth’s mass references: gravitational coefficient (GM) of the Earth (degree 0), geocenter motion (degree 1), Earth’s figure axis orientation (degree 2).

We present results of a self-consistent determination of these three Earth’s mass references. We compare the degree-1 results of SLR-only, DORIS-only, and GPS-only estimations based on Jason-2, to variations inferred from satellite laser tracking to the Ajisai, LAGEOS, LARES, Starlette, and Stella satellites, making the most of independent measurements from different satellite characteristics and techniques. Estimates of the degree-0 and 2 spherical harmonics are only based on the latter geodetic missions.

The results derived aim at better understanding how the associated errors propagate into the scale, origin and orientation of the Terrestrial Reference Frame, while addressing possible implications to the degree-2 Love numbers and corresponing pole tide correction.

 

Oral presentation show times:

Room Start Date End Date
Lagoa Das 7 Cidades Thu, Sep 27 2018,17:30 Thu, Sep 27 2018,17:45
Alexandre Couhert
CNES
France
alexandre.couhert@cnes.fr