Geodesy is concerned with measuring and mapping the shape of the Earth's surface, to the benefit of all branches of Earth sciences and has many practical applications. Although surveying techniques go back thousands of years, it traditionally involves taking very precise three-dimensional positioning of points. It is the means by which the surface of the Earth is mapped and is also essential in the field of engineering and construction.
Accurate surveying relies on knowledge of the Earth's gravity field, which defines the horizontal. However, as a result of a number of factors, such as the fact that mountains and ocean trenches make the surface of the planet uneven and materials within the Earth's interior are not uniformly distributed, the force of gravity actually varies slightly from place to place on the surface of the Earth.
Due for launch in early 2008, ESA's gravity mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) will provide an extremely accurate and unique picture of the Earth's gravity field and geoid. The geoid – which is defined by the Earth's gravity field – is a surface of equal gravitational potential and serves as a reference point from which to map all topographical features on the planet. GOCE will provide a model of the geoid with unprecedented accuracy and will not only be of importance in the field of geodesy, but will also lead to new insights into ocean circulation, climate change, sea-level rise, earthquakes and volcanism.
Starting in Beijing, and travelling through central China to Lhasa then on to the Tibetan Plateau and ending in Shanghai, the Geodetic Journey, which is supported by ESA, will document methods of ancient surveying through to modern Earth observation. The team, made up of experts from the Norwegian Mapping and Cadastre Authority and the Chinese State Bureau of Surveying and Mapping, will promote science and technology focusing on past and present achievements within surveying and mapping, geodesy and applications to climate-change research, geo-hazards and the water cycle.
Over the last 10 years an improved knowledge of the geoid has revolutionised height determination on land by GPS satellites. However, there remain discrepancies - as in the example of Mount Everest where the official height in 1999 was stated as 8850 m, but the Chinese official survey in 2005 stated it as being 8844.43 m. Although this discrepancy may not seem huge when referring to the highest point on Earth, a global unified height system would iron out the main errors so that mountain ranges on one continent could be accurately measured against those on the other side of the world. Given the harsh and remote environments of many of the Earth's large mountain ranges such as the Himalayas or the Andes, an accurate map of the gravity field acquired from space will contribute significantly to geodesy and surveying.
"Measuring our planet's peaks using a standardised reference will help us better understand the Earth. GOCE will result in an improved accuracy of the geoid and will facilitate the establishment of a unified global height system so that heights of the highest mountains in the world can be directly compared", said Bente Lilja Bye, Research Director from the Norwegian Mapping and Cadastre Authority. "Another benefit will be an improvement in our capabilities to predict the behaviour of the Earth, and hence provide information needed to help mitigate disasters and economically damaging events."
Mariangela D'Acunto | alfa
New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg
Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences