Dynamical Determination of Origin and Scale in the Earth System from Satellite Laser Ranging

Satellite laser ranging (SLR) has monitored for a long time the continuous redistribution of mass within the Earth system through concomitant changes in the Stokes’ coefficients of the terrestrial gravity field. JCET’s latest analysis of the 1993-present SLR data set from LAGEOS and LAGEOS 2 data for the IERS (International Earth Rotation Service) Terrestrial Reference Frame (ITRF) includes the weekly monitoring of such compound changes in the low degree and order harmonics. Along with the static parameters of the TRF we have determined a time series of variations of its origin with respect to the center of mass of the Earth system (geocenter). These estimates provide a measure of the total motion due to all unaccounted sources of mass transport within the Earth system and can be used to either complement the estimates from the future missions or to validate them through comparisons with their estimates for the same quantities. The data were reduced using NASA Goddard’s GEODYN and SOLVE II software, resulting to a final RMS error of ~8 mm.