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Seasonal Variations of the Earth's Gravitational Field: An Analysis of Atmospheric Pressure, Ocean Tidal, and Surface Water ExcitationMonthly mean gravitational field parameters (denoted here as C(sub even)) that represent linear combinations of the primarily even degree zonal spherical harmonic coefficients of the Earth's gravitational field have been recovered using LAGEOS I data and are compared with those derived from gridded global surface pressure data of the National meteorological center (NMC) spanning 1983-1992. The effect of equilibrium ocean tides and surface water variations are also considered. Atmospheric pressure and surface water fluctuations are shown to be the dominant cause of observed annual C(sub even) variations. Closure with observations is seen at the 1sigma level when atmospheric pressure, ocean tide and surface water effects are include. Equilibrium ocean tides are shown to be the main source of excitation at the semiannual period with closure at the 1sigma level seen when both atmospheric pressure and ocean tide effects are included. The inverted barometer (IB) case is shown to give the best agreement with the observation series. The potential of the observed C(sub even) variations for monitoring mass variations in the polar regions of the Earth and the effect of the land-ocean mask in the IB calculation are discussed.
Document ID
19990076692
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Dong, D, (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Gross, R.S. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Dickey, J. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Date Acquired
August 19, 2013
Publication Date
April 1, 1996
Publication Information
Publication: Geophysical Research Letters
Volume: 23
Issue: 7
ISSN: 0094-8534
Subject Category
Geosciences (General)
Report/Patent Number
Paper-96GL00740
Distribution Limits
Public
Copyright
Other