A new global mode of Earth deformation: seasonal cycle detected

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1126/science.1065328.

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Authors

Geoffrey Blewitt, David Lavallee, Peter John Clarke , Konstantin Nurutdinov

Abstract

We have detected a global mode of Earth deformation that is predicted by theory. Precise positioning of GPS sites distributed worldwide reveals that in February to March the northern hemisphere compresses (and the southern hemisphere expands), such that sites near the North Pole move downward by 3.0 mm, and sites near the equator are pulled northwards by 1.5 mm. The opposite pattern of deformation occurs in August to September. We identify this pattern as the degree-one spherical harmonic response of an elastic Earth to increased winter loading of soil moisture, snow cover, and atmosphere. Data inversion shows the load moment’s trajectory as a great circle traversing the continents, peaking at 6.9e22 kg m near the North Pole in winter, indicating inter-hemispheric mass exchange of 1.0±0.2e16 kg.

DOI

https://doi.org/10.31223/osf.io/yjeqv

Subjects

Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Other Environmental Sciences, Other Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics

Keywords

geocenter, geocentre, global deformation, Global Positioning System (GPS), seasonal cycle, spherical harmonic, surface mass loading

Dates

Published: 2017-11-13 18:07

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License

CC BY Attribution 4.0 International

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