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Bureau Gravimetrique International ( BGI) R ole and Services to Terrestrial Gravimetry S . Bonvalot , G . Balmino , F. Reinquin , A . Briais , G. Gabalda , L. Seoane Bureau Gravimetrique International ( BGI) Toulouse , France H. Wilmes , H. Wziontek - PowerPoint PPT Presentation
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Bureau Gravimetrique International (BGI)Role and Services to Terrestrial Gravimetry
S. Bonvalot, G. Balmino, F. Reinquin, A. Briais, G. Gabalda, L. Seoane
Bureau Gravimetrique International (BGI)Toulouse, France
H. Wilmes, H. Wziontek
Federal Agency for Cartography and Geodesy (BKG)Frankfurt/Leipzip, Germany
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
OBJECTIVES / PARTNERSHIPS
BKG Germany Absolute
gravimetry
CU AustraliaWorld Gravity Map
Int. Geoid ServiceNewton’s Bulletin
International schools
NGA, USA World Gravity Map
French supporting organizations 13 Institutions & Universities
International collaborations (mostly within IAG/IGFS frame) some examples
BIPMAbsolute
gravimetry
Compilation, validation & long term archiving of gravimetric dataAims at facilitating the diffusion of gravity information to the scientific community
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Global databases & products Relative & absolute gravity measurements
Gravity modeling Ex : World Gravity Map
Software developments Gravity analysis, modeling, terrain correction…
Field surveys Relative & Absolute (Europe, South America, Africa, Asia…)
Education / Summer schools Collab. With IGeS
IAG commission & working groups in gravimetry IGFS, GGOS, CCM-BIPM, etc.
Instrumentation Support from French teams for a future cold atom gravimeter (AQG by MuQuans)
MAIN ACTIVITIES
Focus here on main data & products recently provided by BGI
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Relative land measurements(a few millions of data)
Relative marine measurements(> 10 millions of data)
Reference stationsIGSN71 / Potsdam networks(>4500 stations)
Absolute measurements(started in 2007)
OVERVIEW OF THE GLOBAL GRAVITY DATABASES
Consultation / Request from the BGI website http://bgi.obs-mip.fr
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Motivation
Increasing number of AG instruments few µGal level measurements in lab & field
Need to register AG measurements and to share information globally
Scientific interest / Benefits
Reference network for relative gravity surveys & relative meter calibration
Support and registry for inter-comparisons of AG instruments
Study of static and temporal gravity changes / Link to other geophysical observations
New International Gravity Reference System (replacement of IGSN71)
Joint operation by BKG and BGI since 2007as a contribution to IAG / IGFS
ABSOLUTE GRAVITY DATABASE
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Web-based user interface developed in 2008Available at 2 mirrored sites : BKG: http://agrav.bkg.bund.de/agrav-meta/
BGI : http://bgi.obs-mip.fr
Overview about stations, observation, epochs, gravimeters and institutions
Current status of the database - 08/2013768 stations / 2607 observations / 45 instruments / 41 institutions (24 countries)
ABSOLUTE GRAVITY DATABASE
Who measured ? Where and When ?
Provision of contact information
Sharing results (gravity values)
Data repository and long term availability
Upload of data done by users using their own ‘project’-files (ask for login)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
ABSOLUTE GRAVITY DATABASE
New web application AGrav is under development at BKG
Improved functionalities New interactive map (OpenStreetMap) Clustering of stations Classification of available networks Plot of gravity time series Report generator Bibliographic references to related
publications …
Similar structure but new functionalities
(Wziontek et al., 2013, 17th International Symposium on Earth Tides, Warsaw, Poland)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
ABSOLUTE GRAVITY DATABASE
Relation of AG and SC (GGP) stations
New web application AGrav is under development at BKG
(Wziontek et al., 2013, 17th International Symposium on Earth Tides, Warsaw, Poland)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
ABSOLUTE GRAVITY DATABASE
Link to SG data (common sites) Data structure compatible to GGP Possibility of download SG time series Plots of SG/AG time series …
(Wziontek et al., 2013, 17th International Symposium on Earth Tides, Warsaw, Poland)
Expected to make better reliability between AG and SG observations
New web application AGrav is under development at BKG
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Project initiated in 2008
Collaboration with the Commission for the Geological Map of the World (CGMW)
Initially aimed at providing worldwide Bouguer & Isostatic anomalies
Contribution to the global geological & geophysical mapsedited by CGMW / UNESCO for education and research purposes
(extensively used in geophysical interpretation but usually computed at regional scale)
Challenging project providing new global products
Based on rigorous and homogeneous computation of anomalies in spherical geometry
Including global high resolution terrain corrections (1 arc-minute)
Using up-to-date global models for gravity (EGM08, DTU10) and topography
WORLD GRAVITY MAP (WGM)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Proposed approach (analytic approach : Spherical Harmonic)
Computation of the whole terrain effect (Bouguer shell + Terrain Corrections)
Based on new developments by G. Balmino to perform SHA/SHS (up to d/o 32600)
See : Balmino et al. (Jounal of Geodesy, 2012)
Geodetic definition
High resolution computations (d/o 10800)
Realistic Earth model (all surface masses )
Continents
Oceans
Inner sears – Lakes
Ice caps
WORLD GRAVITY MAP (WGM)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Land b.s.l.Chott Algeria-TunisiaQattara (depression)Death ValleyNetherlands (part)Turfan (depression)
Closed seasAral seaCaspian seaDead sea
LakesBaikalBalkachBear lakeConstanceErieEyreHuronLadogaLemanMalawiMaracaiboMichiganOnegaSaltonSlavesSuperiorTanganykaTiberiadeTiticacaVictoriaWinnipegYssyk-Koul
Oceans
Ice capsOver GreenlandOver Antarctica
Lands
Ice shelvesRossRonne-Filchner,Larsen, Amery
Data sourcesETOPO1 (surface & bedrock)
SRTM30ILEC Data base
Densities (kg/m3)Crust (2670)Upper Mantle (3270)Ocean water (1027) Ice (917)
Surface masses taken into account(according to their position w.r.t. mean sea level)
WORLD GRAVITY MAP (WGM)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
1’x1’ grid of spherical terrain corrections(applicable to any observed gravity field)
Computation of gravity contribution of surface masses (derived from ETOPO1)Lands / Oceans / Inland seas & major lakes / Ices (Antarctica, Greenland)
WORLD GRAVITY MAP (WGM)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Spherical complete Bouguer anomaly(based on EGM08 / DTU10 gravity models)
WORLD GRAVITY MAP (WGM)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Spherical complete isostatic anomaly (Airy-Heiskanen)(based on EGM08 / DTU10 gravity models)
WORLD GRAVITY MAP (WGM)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Free-air anomaly (Molodensky)(based on EGM08 / DTU10 gravity models)
WORLD GRAVITY MAP (WGM)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Free-air anomaly (Molodensky)(based on EGM08 / DTU10 gravity models)
WORLD GRAVITY MAP (WGM)
Version 1.0 (WGM2012) achieved in 2012
Bonvalot et al. (World Gravity Map, 2012) ; Balmino et al. (Jounal of Geodesy, 2012)
Set of 3 spherical anomalies (Bouguer, Isostatic, surface free-air)Distributed by CGMW / UNESCO : http://ccgm.free.fr
Digital grids of anomalies downloadable at 2’x2’ : http://bgi.obs-mip.fr
On-line tool for grid extraction and visualisation
Upgraded versions as soon as new EGM is available (including GOCE and new surface data)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
WGM2012 gravity anomalies and global tectonic map (in progress)
OTHER WORK IN PROGRESS
Information derived from the global tectonic map Tectonic plates
Major geological units & ages (oceanic crust, continental crust)
Major faults (thrust, subduction, transform…)
Sedimentary basins, igneous and effusive rocks, etc…
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
WGM2012 gravity anomalies and global tectonic map (in progress)
OTHER WORK IN PROGRESS
Better interpretation / teaching of the Earth’s gravity anomalies at large scale
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Interactive application for 3D view (based on NASA World Wind)
OTHER WORK IN PROGRESS
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Interactive application for 3D view (based on NASA World Wind)
OTHER WORK IN PROGRESS
WGM2012 Complete Bouguer anomaly
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Interactive application for 3D view (based on NASA World Wind)
OTHER WORK IN PROGRESS
WGM2012 free-air anomaly
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Interactive application for 3D view (based on NASA World Wind)
OTHER WORK IN PROGRESS
WGM2012 complete Isostatic anomaly
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
Interactive application for 3D view (based on NASA World Wind)
OTHER WORK IN PROGRESS
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
OTHER WORK IN PROGRESS
Gravity anomalies and global tectonics (in progress)
Interactive application for 3D view (based on NASA World Wind)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
RECENT ON-LINE TOOLS
Prediction of gravity at a given site theoretical & interpolated values
Requests for metrology purpose needing an estimation of the local gravity
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
On-line availability of « old » BGI Bulletins collection (1959-2002)
RECENT ON-LINE TOOLS
Achieved in August 2013 (contains internal matters + contributing papers)
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia
CONCLUSIONS / PERSPECTIVES To provide relevant services to IAG scientific users
Global gravity database : Compilation / Re-processing of surface gravity data
Global / Regional gravity modeling : Including surface and GOCE data
Earth’s Reference Gravity System : Contribution to the realization of the future system
Active collaborations in progress within IGFS
BKG (Germany), IGeS (Italy), NGA (USA), DTU (Denmark), CU (Australia)…
Feel free to contact BGI !
BGI : http://bgi.obs-mip.fr
BKG: http://agrav.bkg.bund.de/agrav-meta
Information update from users is still very welcome !
With surface gravity observations (land & marine surveys) – Products from airborne surveys ?
With absolute gravity measurements (FG5, A10 or others)
With any software, documentation believed to be useful for other scientists
IAG Symposium on Terrestrial Gravimetry : Static and Mobile Measurements – September 1 7– 20, 2013 – St Petersburg, Russia