[Alumnos] Seminario jueves 15/03 - 14:30 hs - Dr.-Ing. Hartmut Wziontek

[Secretaría de Ciencia y Técnica]

*Estimados,*

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*El próximo jueves 15/03 tendremos el siguiente Seminario *a las 
1*4*:*3*0 hs. en el Salón Meridiano. Los esperamos 15 minutos antes 
**con café y galletitas.

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Secretaría de Ciencia y Técnica
FCAG*

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Seminario:Dr.-Ing. Hartmut Wziontek

Department G4 - Gravity Metrology

Federal Agency for Cartography and Geodesy (BKG)

Leipzig, Germany


Título: Absolute and Superconducting Gravimetry in Argentina


Resumen:High accuracy absolute and relative terrestrial gravity 
observations provide the basis for a stable and homogeneous gravity 
reference system and long term monitoring of the system Earth.

Recently both observation methods were established at the 
Argentinian-German geodetic observatory AGGO close to the city of La 
Plata and are operated in close cooperation of Argentinean and German 
colleagues. The observations of both gravimeters contribute to global 
initiatives, such as the International database for absolute gravity 
observations AGrav, jointly operated by the International Gravity Bureau 
(BGI, Toulouse, France) and BKG and the International Geodynamics and 
Earth Tide Service (IGETS), both are service of the International 
Association of Geodey (IAG). The location of AGGO at the southern 
hemisphere makes these efforts most important.

After short a general introduction into spatial and temporal gravity 
field variations, the working principles of both instrument types are 
explained. While the state-of-the art absolute gravimeters (AG) still 
realize the free fall of a macroscopic test mass, the development of a 
new technology based on atom interferometry opens a new field of 
applications. Contrary to absolute gravity observations, which are 
usually limited to short observation epochs, Superconducting gravimeters 
(SG) are the most precise but stationary relative instruments, allowing 
to monitor temporal gravity changes with highest resolution. The 
combination of collocated observations of both types results in the best 
possible realization of an absolute reference function for time 
variations in gravity and serves as a reference for the comparison and 
validation of different AGs, ensuring their traceability. Considering 
aspects of metrology, such comparisons are an essential part of the new 
absolute gravity reference system, which is currently established 
according to IAG resolution No. 2 of 2015. For this purpose, a globally 
homogenous absolute level for gravity observations should be transferred 
to the national networks and infrastructure, which is now supported by AGGO.

Long term stable precise gravity observations at selected station become 
important in many fields, reaching from monitoring of geodynamics 
processes like the glacial isostatic uplift or regional deformation 
effects up to local water storage changes or the comparison with GRACE 
derived gravity field models. Examples are presented for stations and 
different projects.

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