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Subdaily signals in GPS observations and their effect at semiannual and annual periods


King, MA and Watson, CS and Penna, NT and Clarke, PJ, Subdaily signals in GPS observations and their effect at semiannual and annual periods, Geophysical Research Letters, 35, (3) Article L03302. ISSN 0094-8276 (2008) [Refereed Article]

DOI: doi:10.1029/2007GL032252


Estimates of seasonal geophysical loading from GPS may be biased by propagated unmodeled subdaily signals. Although the major geophysical signals at semidiurnal and diurnal frequencies are now routinely modeled in GPS analyses, the characteristics of unmodeled or mismodeled subdaily signals are not well known. Here, using site coordinates estimated every 5 minutes, we examine the subdaily coordinate spectral characteristics for ~90 global GPS sites. Unmodeled signals with amplitudes at the 10 mm level are present at frequencies between ~1/day and the Nyquist frequency. These are shown to propagate into 24 h solutions with (among other frequencies) annual and semiannual periods with amplitudes up to 5 mm, with a median amplitude in the height component of 0.8 mm (annual) and 0.6 mm (semiannual). They are shown to bias low-degree spherical harmonics estimates of geophysical loading at the level of 510%, although the exact effect will be network dependent.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geophysics
Research Field:Geodesy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:King, MA (Professor Matt King)
UTAS Author:Watson, CS (Dr Christopher Watson)
ID Code:54501
Year Published:2008
Web of Science® Times Cited:66
Deposited By:Geography and Environmental Studies
Deposited On:2009-02-24
Last Modified:2014-12-08

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