气候变化领域集成服务门户(CCPortal): ITRF2014, Earth Figure Changes, and Geocenter Velocity: Implications for GIA and Recent Ice Melting

CCPortal

DOI	10.1029/2019JB018333
	ITRF2014, Earth Figure Changes, and Geocenter Velocity: Implications for GIA and Recent Ice Melting
	Métivier L.; Rouby H.; Rebischung P.; Altamimi Z.
发表日期	2020
ISSN	21699313
卷号	125 期号:2
英文摘要	Using a selection of Global Navigation Satellite System vertical velocities from the latest solution of the International Terrestrial Reference Frame (ITRF) ITRF2014, we calculate the degree-1 and degree-2 spherical harmonics coefficients (SHC) of the solid Earth figure changes at different dates, with realistic errors that take into account the inhomogeneity of the network. We find that the SHC are globally close to zero except the zonal coefficients, which show values notably larger than those derived from different glacial isostatic adjustment (GIA) models and which have tended to increase during the time span of observations. We show that these differences are most probably due to global recent ice melting (RIM). Assuming elastic RIM deformation, we then investigate the Earth's geocenter velocity and the geoid oblateness time evolution (J2-rate) derived from our SHC estimations. The obtained geocenter velocity reaches 0.9 ± 0.5 mm/year in 2013 with a z-component of 0.8 ± 0.4 mm/year, which is slightly larger than previous estimations. We compare our J2-rate estimations with observations. Our estimations show a similar acceleration in J2 after 2000. However, our estimates are notably larger than the observations. This indicates either that the J2-rate due to GIA processes is lower than expected (as proposed by Nakada et al., 2015, 2016) or that the deformation induced by RIM is not purely elastic, or both. Finally, we show that viscous relaxation or phase transitions in the mantle transition zone may only partly explain this discrepancy. This raises the question of the accuracy of current mass estimations of RIM and GIA models. ©2020. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/188011
作者单位	Université de Paris, Institut de Physique du Globe de Paris, CNRS, IGN, Paris, France; ENSG-Géomatique, IGN, Marne-la-Vallée, France; Ecole Normale Supérieure, Laboratoire de Géologie, UMR 8538, Paris, France
推荐引用方式 GB/T 7714	Métivier L.,Rouby H.,Rebischung P.,et al. ITRF2014, Earth Figure Changes, and Geocenter Velocity: Implications for GIA and Recent Ice Melting[J],2020,125(2).
APA	Métivier L.,Rouby H.,Rebischung P.,&Altamimi Z..(2020).ITRF2014, Earth Figure Changes, and Geocenter Velocity: Implications for GIA and Recent Ice Melting.Journal of Geophysical Research: Solid Earth,125(2).
MLA	Métivier L.,et al."ITRF2014, Earth Figure Changes, and Geocenter Velocity: Implications for GIA and Recent Ice Melting".Journal of Geophysical Research: Solid Earth 125.2(2020).