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Lookup NU author(s): Dr Liz Petrie, Professor Matt King, Professor Philip Moore, Dr David Lavallee
This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Geophysical Union, 2010.
For re-use rights please refer to the publisher's terms and conditions.
We describe how GPS time series are influenced by higher-order ionospheric effects over the last solar cycle (1995-2008) and examine implications for geophysical studies. Using 14 years of globally reprocessed solutions, we demonstrate the effect on the reference frame. Including second-and third-order ionospheric terms causes up to 10 mm difference in the smoothed transformation to the International Terrestrial Reference Frame (ITRF) 2005, with the Z translation term dominant. Scale is also slightly affected, with a change of up to similar to 0.05 ppb. After transformation to ITRF2005, residual effects on vertical site velocities are as high as 0.34 mm yr(-1). We assess the effect of the magnetic field model on the second-order term and find a time-varying difference of 0-2 mm in the Z translation. We also assess the effect of omitting the third-order term. We find that while the second-order term is responsible for almost all the Z translation effects, it is the combination of the second-and third-order terms that causes the effect on scale. Comparison of our GPS reprocessing with ITRF2005 suggests that GPS origin rates may vary with time period. For example, we find Z translation rates of -0.82 +/- 0.17 mm yr(-1) for 1995-2008 and 0.17 +/- 0.24 mm yr(-1) for 1995-2005. If GPS were to contribute to origin rate definition for future ITRFs, higher-order ionospheric corrections would need to be applied due to their effect on translation parameters during solar maximum.
Author(s): Petrie EJ, King MA, Moore P, Lavallee DA
Publication type: Article
Publication status: Published
Journal: Journal of Geophysical Research: Solid Earth
Year: 2010
Volume: 115
Issue: B3
Print publication date: 24/03/2010
Date deposited: 26/07/2010
ISSN (print): 1934-8843
ISSN (electronic): 1934-8592
Publisher: American Geophysical Union
URL: http://dx.doi.org/10.1029/2009JB006677
DOI: 10.1029/2009JB006677
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