{"id":913373,"date":"2026-10-02T11:10:15","date_gmt":"2026-10-02T11:10:15","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/913373\/"},"modified":"2026-10-02T11:10:15","modified_gmt":"2026-10-02T11:10:15","slug":"gnss-study-the-earth-is-becoming-rounder","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/913373\/","title":{"rendered":"GNSS study: The Earth is becoming rounder"},"content":{"rendered":"

\"AImage courtesy NASA<\/p>\n

A new suggests the solid Earth\u2019s shape is becoming slightly less flattened, a finding that could be important for research into climate change and other fields.<\/p>\n

The study, by C. Kotsakis of the Department of Geodesy and Surveying at the Aristotle University of Thessaloniki in Greece, looked at how the shape of our planet is slowly changing over time.<\/p>\n

The Earth isn\u2019t a perfect sphere, but rather an oblate spheroid \u2014 slightly flattened at the poles and bulging at the equator.<\/p>\n

But that shape isn\u2019t fixed; it changes due to natural processes such as melting ice, shifting land, and changes in the Earth\u2019s surface and interior.<\/p>\n

\u201cTo better understand these changes, we used satellite-based measurements of how the Earth\u2019s surface moves up or down in different places,\u201d the author writes in the study\u2019s paper, which has been published<\/a> in the journal JGR Solid Earth.<\/p>\n

\u201cWe developed a method to analyse this data and track whether Earth is becoming more or less flattened over time. Our results indicate an acceleration of polar uplift accompanied by a comparably increasing rate of equatorial subsidence. This means that solid Earth\u2019s overall shape is becoming slightly less flattened.<\/p>\n

\u201cWe further find that this geometric change is not fully mirrored in the Earth\u2019s gravity field, indicating that the geometric response of the solid Earth and the gravity field response to mass-redistribution do not evolve identically.\u201d<\/p>\n

According to the author, the findings are important because they help scientists understand how the planet responds to melting glaciers and shifting water.<\/p>\n

\u201cThis kind of knowledge is essential for tracking climate change and its impact on Earth\u2019s long-term behaviour.\u201d<\/p>\n

Earth\u2019s poles are rising<\/p>\n

By linking satellite measurements of changing altitude across Earth\u2019s surface from 1997 to 2015 to the planet\u2019s shape, Kotsakis found that the Earth\u2019s poles are rising by 0.5 to 1 millimetres per year, slowly un-squashing our planet\u2019s slightly flattened shape.<\/p>\n

Not only that, but the rounding effect also seems to be accelerating over time, with the poles rising an extra 0.4 millimetres per year faster every decade. As ice sheets melt and reduce the force acting on the Earth at the poles, the equator is gradually cinching in as the poles push upwards, moulding our planet into a more spherical shape.<\/p>\n

\u201cThe analysis of GNSS vertical velocity fields from the ITRF2014 frame solution, complemented by selected polar stations from ITRF2020, reveals coherent trends in solid Earth\u2019s figure change over the period 1997\u20132015,\u201d the author writes.<\/p>\n

\u201cPolar regions exhibit an accelerating uplift that increases from approximately 0.5 mm\/yr in the late 1990s to nearly 1 mm\/yr in the most recent epoch, while equatorial regions display a compensating subsidence of comparable magnitude.\u201d<\/p>\n

The author says this is \u201c\u2026 indicative of a progressive reduction in the solid Earth\u2019s flattening, with inferred accelerations on the order of 0.4 mm\/yr per decade\u201d.<\/p>\n

In conclusion, the author writes that \u201c\u2026 this work demonstrates that global GNSS vertical velocity fields can be used to detect not only secular changes but also accelerations in Earth figure parameters associated with contemporary surface mass transport\u201d.<\/p>\n

\u201cContinued improvements in global GNSS coverage, velocity estimation, and the treatment of viscoelastic and hydrological effects will further strengthen the role of GNSS as an independent constraint on Earth system change and its ongoing impact on the planet\u2019s geometry and gravity field.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"Image courtesy NASA A new suggests the solid Earth\u2019s shape is becoming slightly less flattened, a finding that…\n","protected":false},"author":2,"featured_media":913374,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[64,63,129,103576,3189,128],"class_list":["post-913373","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-au","tag-australia","tag-earth","tag-gnss","tag-gravity","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/913373","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=913373"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/913373\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/913374"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=913373"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=913373"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=913373"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}