Premium
Two years of continuous measurements of tidal and nontidal variations of gravity in Boulder, Colorado
Author(s) -
van Dam Tonie M.,
Francis Olivier
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl03780
Subject(s) - gravimeter , geodesy , polar motion , admittance , geology , observatory , hydrostatic equilibrium , meteorology , physics , geophysics , earth's rotation , casing , quantum mechanics , astrophysics , electrical impedance
We report here on the results of an analysis of 2 years of data from NOAA's superconducting gravimeter located at the Table Mountain Gravity Observatory in Boulder, Colorado. Observed tidal parameters, corrected for ocean loading effects, are compared with theoretical tidal parameters predicted for a non‐hydrostatic inelastic Earth model and demonstrate excellent agreement. Tidal residuals, corrected for polar motion and a linear instrument drift are highly correlated with gravity changes measured by two absolute gravimeters over the same time period. The admittance to local pressure is found to be −0.356 µGal/mbar. However, this admittance factor is found to be seasonally and frequency dependent. Correlations between rainfall events and gravity changes are observed. Attempts to model these gravity changes as exponential functions of time were unsuccessful.