The influence of Antarctic ice loss on polar motion: an assessment based on GRACE and multi-mission satellite altimetry

Abstract

Increasing ice loss of the Antarctic Ice Sheet (AIS) due to global climate change affects the orientation of the Earth’s spin axis with respect to an Earth-fixed reference system (polar motion). Here the contribution of the decreasing AIS to the excitation of polar motion is quantified from precise time variable gravity field observations of the Gravity Recovery and Climate Experiment (GRACE) and from measurements of the changing ice sheet elevation from altimeter satellites. While the GRACE gravity field models need to be reduced by noise and leakage effects from neighboring subsystems, the ice volume changes observed by satellite altimetry have to be converted into ice mass changes. In this study we investigate how much individual gravimetry and altimetry solutions differ from each other. We show that due to combination of individual solutions systematic and random errors of the data processing can be reduced and the robustness of the geodetic derived AIS polar motion excitations can be increased. We investigate the interannual variability of the Antarctic polar motion excitation functions by means of piecewise linear trends. We find that the long-term behavior of the three ice sheet subregions: EAIS (East Antarctic Ice Sheet), WAIS (West Antarctic Ice Sheet) and APIS (Antarctic Peninsula Ice Sheet) is quite different. While APIS polar motion excitations show no significant interannual variations during the study period $$2003-2015$$ 2003 - 2015 , the trend of the WAIS and EAIS polar motion excitations increased in 2006 and again in 2009 while it started slightly to decline in 2013. AIS mass changes explain about $$45\%$$ 45 % of the observed magnitude of the polar motion vector (excluding glacial isosatic adjustment). They cause the pole position vector to drift along $$59^{\circ }$$ 59 ∘ East longitude with an amplitude of 2.7 mas/yr. Thus the contribution of the AIS has to be considered to close the budget of the geophysical excitation functions of polar motion.

Combination strategy for consistent final, rapid and predicted Earth rotation parameters

“…concerning climate change (Chen et al 2013;Mitrovica et al 2015;Adhikari and Ivins 2016;Śliwińska et al 2021). Göttl et al (2015Göttl et al ( , 2021 and Chen et al (2017) show that precise EOPs can contribute to improved modelling of effects related to these phenomena. In this context, the International Association of Geodesy (IAG) Inter-Commission Committee on "Geodesy for Climate Research" (ICCC) Joint Working Group (JWG) C.1 "Climate Signatures in Earth Orientation Parameters" investigates the interdependency between variations in the Earth's rotation and the Earth's climate on short and longer time scales (Poutanen and Rósza 2020a).…”

Are Ocean Reanalyses Useful for Earth Rotation Research?

“…Mass motion and redistribution in geophysical fluids excite Earth's wobbles and length‐of‐day changes with varying efficacy on different time scales. While atmospheric contributions to these rotational fluctuations are relatively well determined through reanalysis data sets (Bizouard & Seoane, 2010; Gross et al., 2003, 2004; Neef & Matthes, 2012; Schindelegger et al., 2013), uncertainties increase as one invokes—apart from the somewhat elusive core processes (Kuang et al., 2019; Mound, 2005; Pais & Hulot, 2000)—oceanic (Harker et al., 2021; Marcus et al., 1998; Ponte et al., 1998; Quinn et al., 2019; Zhou et al., 2005), hydrological (Adhikari & Ivins, 2016; Meyrath & van Dam, 2016; Nastula et al., 2019), and cryospheric (J. L. Chen, Wilson, et al., 2013; Göttl et al., 2021) effects in the planet's angular momentum budget. Here we are primarily concerned with modeling the non‐tidal oceanic component in polar motion and length‐of‐day excitations, on time scales from a few days out to several years.…”

Spatial and temporal variation characteristics and attribution analysis of land water storage changes in China

“…In 2002, the GRACE satellite was successfully launched, which can continuously and rapidly detect the mass changes caused by material transport, thus providing a new method for large-scale terrestrial water storage studies (Jiang et al 2021;Tangdamrongsub et al 2021). Currently, GRACE data play an irreplaceable role in the research of terrestrial water storage inversion, Antarctic glacier melting and other fields (Deggim et al 2021;Göttl et al 2021). Fatolazadeh (Fatolazadeh & Goïta 2021) used GRACE data from 2002 to 2017 and GRACE-FO data from 2018 to 2019 to analyze the changes in Canadian terrestrial water storage, and the study showed that in the area around Hudson Bay, Canada, terrestrial water storage increased to 45 mm/a over a 17-year period; Hussain et al (2021) obtained the variation of terrestrial water storage in the Gilgit-Baltistan region by inversion of GRACE data, GLDAS-Noah data and precipitation data from 2003 to 2016, and the study showed that precipitation has a positive correlation with TWS estimated from GRACE and GLDAS-Noah data; Hasan et al (2021) monitored the changes of water storage in the Nile basin in the 20th century based on GRACE, GRACE-FO combined with precipitation and standard drought indicators and predicted the future trends.…”