Contributions of Greenland GPS Observed Deformation From Multisource Mass Loading Induced Seasonal and Transient Signals

Abstract

Global Positioning System (GPS) provides critical geodetic constraints on Earth's elastic response induced by ice and other mass loadings in Greenland. Previous studies focused on long‐term ice mass changes, with relatively fewer studies on transient signals and had used fewer GPS stations. Here we reconstructed 44 Greenland‐wide coastal decadal GPS time series using multichannel singular spectral analysis and quantified the origins of spatiotemporal patterns of transient to seasonal signals. We used an exhaustive list of geophysical processes, including surface mass balance (SMB), atmospheric pressure, continental hydrology, nontidal ocean loading, bedrock thermal expansion, precipitation, runoff, and ice discharge, and identified that most of Greenland's GPS sites exhibit SMB‐induced transient signals during 2012–2015, with maximum displacement reaching 20.45 mm. Analyses of differenced time series between adjacent GPS stations near peripheral glaciers reveal that locally varying seasonal signals are primarily attributable to SMB, followed by atmosphere.

Viscoelastic Love numbers and long-period geophysical effects

“…However, some other signals such as Earth tides (especially the Moon's node of 18.6 yr period) or present-day ice melting (Spada et al 2012;Luthcke et al 2013), could also be affected by viscoelastic rheologies. In most studies (Zhang et al 2019;Li et al 2020), the anelasticity of the Earth's response to surface loading processes, including present-day ice mass loss, is still neglected but should be considered to provide a unique consistent frame of study within other long period loading deformation signals such as GIA (Métivier et al 2020).…”