Contribution of satellite laser ranging to combined gravity field models

Andrea Maier*, Sandro Krauss, Walter Hausleitner, Oliver Baur

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

In the framework of satellite-only gravity field modeling, satellite laser ranging (SLR) data is typically exploited to recover long-wavelength features. This contribution provides a detailed discussion of the SLR component of GOCO02S, the latest release of combined models within the GOCO series. Over a period of five years (January 2006 to December 2010), observations to LAGEOS-1, LAGEOS-2, Ajisai, Stella, and Starlette were analyzed. We conducted a series of closed-loop simulations and found that estimating monthly sets of spherical harmonic coefficients beyond degree five leads to exceedingly ill-posed normal equation systems. Therefore, we adopted degree five as the spectral resolution for real data analysis. We compared our monthly coefficient estimates of degree two with SLR and Gravity Recovery and Climate Experiment (GRACE) time series provided by the Center for Space Research (CSR) at Austin, Texas. Significant deviations in C 20 were noted between SLR and GRACE; the agreement is better for the non-zonal coefficients. Fitting sinusoids together with a linear trend to our C 20 time series yielded a rate of (-1.75 ± 0.6) × 10 -11 /yr; this drift is equivalent to a geoid change from pole to equator of 0.35 ± 0.12 mm/yr or an apparent Greenland mass loss of 178.5 ± 61.2 km 3 /yr. The mean of all monthly solutions, averaged over the five-year period, served as input for the satellite-only model GOCO02S. The contribution of SLR to the combined gravity field model is highest for C 20 , and hence is essential for the determination of the Earth's oblateness.

Original languageEnglish
Pages (from-to)556-565
Number of pages10
JournalAdvances in Space Research
Volume49
Issue number3
DOIs
Publication statusPublished - 1 Feb 2012
Externally publishedYes

Keywords

  • GOCO
  • Gravity field
  • Satellite laser ranging
  • Temporal variation

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)

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