The impact of data from the new missions in the development of future gravity models
Abstract
JCET is contributing to NIMA efforts to enhance the geopotential model underlying the World Geodetic System 84 (WGS 84), and in particular, with the incorporation of data from new missions such as CHAMP and GRACE at present, and GOCE in the future. One of the many enhancements that the new development incorporates is the modeling of temporal variations for the long wavelength components of the field, in order to avoid aliasing of these signals and a consequent degradation in the quality of the new model. The Terrestrial Reference Frame (TRF) plays an important role in the multi-technique monitoring of temporal variations in the gravitational field and its very low degree and order components, as well as changes in the inertia tensor as a result of angular momentum exchanges in the Earth system. Currently, and until we accumulate several years of GRACE data, the best data source for determining these variations are satellite laser ranged geodetic targets (such as the LAGEOS, ETALON, etc.). We are now routinely analyzing Satellite Laser Ranging (SLR) data from ETALON 1 and 2, along with our nominal data set from LAGEOS 1 and LAGEOS 2 for this effort. While the data from these satellites provide the definition of the underlying TRF, its crust-fixed orientation, and the temporal variations in the long wavelength, the detailed components of the gravitational model will be primarily determined from the data of dedicated missions such as CHAMP, GRACE, and GOCE in the future. We present here preliminary results of a new analysis of our expanded data set for the definition of the harmonics of the geopotential. The data were reduced using the NASA Goddard GEODYN/SOLVE II software. We discuss and compare our results with other solutions based on data from the new missions alone, or in combination with other satellite and surface gravimetric data.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....7952P