Acta Geodynamica et Geomaterialia

Title: GEOPHYSICAL FLUIDS FROM DIFFERENT DATA SOURCES, GEOMAGNETIC JERKS, AND THEIR IMPACT ON EARTHS ORIENTATION
Authors: Vondrák Jan and Ron Cyril
DOI: 10.13168/AGG.2016.0005
Journal: Acta Geodynamica et Geomaterialia, Vol. 13, No. 3 (183), Prague 2016
Full Text: PDF file (3.1 MB)
Keywords: Polar motion, length-of-day, free core nutation, geophysical excitations, geomagnetic jerks
Abstract: Recently we studied the effects of geophysical fluids (atmosphere, oceans) and geomagnetic jerks in Earth’s orientation in space (Vondrák and Ron, 2010; Ron and Vondrák, 2011). To this end, we used the American NCEP/NCAR model of the atmosphere and ECCO model of the oceans (Vondrák and Ron, 2015). Here we concentrate on other available models of geophysical fluids, such as ERA and MERRA for the atmosphere, and OMCT for the oceans, and compare the results obtained with all of them. We also test the hypothetic effect of geomagnetic jerks together with these alternative models and study how much the agreement with the observed Earth Orientation Parameters is improved. By using numerical integration of all five Earth orientation parameters, we demonstrate that different models of atmospheric/oceanic excitations lead to slightly different results, fitting relatively well with their observed values but showing changes both in amplitude and phase. In all cases the agreement improves substantially when the effect of geomagnetic jerks is added to geophysical fluids, and the differences in amplitude/phase almost disappear.