The geocentre inversion based on the global climate models and GPS site displacements

• Published in: Survey review - Directorate of Overseas Surveys Vol. 50; no. 363; pp. 513 - 521
• Main Authors: Yu, Nan, Cheng, Pengfei, Cheng, Yingyan, Wen, Hanjiang, Kuang, Kaifa, Cao, Xinyun
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 02.11.2018
• Subjects: Degree-1 load deformation; Geocentre motion; GPS Sites displacement; ITRF; Surface load variation
• ISSN: 0039-6265; 1752-2706
• DOI: 10.1080/00396265.2017.1329077

The geocentre is not static, reflecting the relative motion between CM and the ITRF origin. The degree-1 deformation of the earth surface involves the horizontal transport of the earth's fluid envelope including mass transport of the non-tidal ocean, dynamics of atmosphere, and hydrological mass redistribution in the continents, which can be estimated through the global climate models and the global GNSS-based deformation monitoring. We use climate models of ECCO, NCEP and GLDAS to calculate the geocentre motion caused by the non-tidal ocean, atmosphere, and ground water, respectively. We calculate the 'surface load moment' using the displacement of 132 sites of IGS05, and then inverse geocentre by GPS. We find that the higher-degree terms would be induced in the degree-1 computing process and they will result in unmodelled errors. The number of GPS sites for inversion is not the more the better, while the even distribution is much more critical.