Joint Working Group (JWG)
Between International Gravity Field
Service (IGFS) and the IAG Commission 2
Chair: Dr.
Jianliang Huang (Geodetic Survey Division, CCRS, NRcan, Canada) - jianhuan@NRCan.gc.ca
Vice-chair:
Dr. Christopher Kotsakis (Aristotle University of Thessaloniki, Greece)
The CHAMP and GRACE satellite gravity missions,
along with the upcoming GOCE mission, are and will be mapping the Earth’s
gravity field with significantly increasing accuracy and spatial resolution.
The data obtained from these missions are being and will be used to develop a
series of new static satellite-only gravity models down to 150 – 200 km
wavelength, as well as combined Earth Gravity Models (EGMs) down to about 20 km
wavelength. The evaluation of such global EGMs is commonly based on comparisons
with other “external” data sets that depend on the same gravity field. The
various centers responsible for the development of these models routinely
perform such comparisons using a variety of validation data sets such as geoid
heights from GPS and leveling heights, airborne and surface gravity
measurements, marine geoid heights from mean oceanographic sea surface
topography models and altimetry observations, orbits from other geodetic and
altimetry satellites etc.
In response to the call of having an independent
and coordinated initiative for the evaluation of the new EGMs, a new Joint
Working Group (JWG) has been established between IGFS and the IAG Commission 2.
The main objective of the JWG is to develop standard validation/calibration
procedures, and to perform the quality assessment of GRACE-, CHAMP- and
GOCE-based satellite-only and combined solutions for the static Earth’s gravity
field. The external data sets that will be used for such purposes include
mainly GPS-leveling data, airborne and surface gravity data, mean oceanographic
sea surface topography models and altimetry data, orbit data from other
geodetic and altimetry satellites and astro-geodetic deflection data etc.
Another equally important evaluation is with
respect to temporal variation of the Earth’s gravity field derived from the
GRACE monthly gravity solutions. The repeated absolute/relative gravity
measurements and super-conducting gravity observations provide the most
accurate temporal variation on the ground. As part of the
initiative, validation/calibration methods for temporal gravity variation will
be explored.
1.
The JWG
creates opportunities through communication and workshops/conferences for
international cooperation to develop and propose standard methods for
evaluating global EGMs using external geodetic and oceanographic data. A
specific research area of interest will be the issue of how to handle the
different spectral content of satellite-based global gravity field models and
terrestrial gravity data.
2.
The JWG
defines a set of synthetic data to test the feasibility and the performance of
various evaluation methods for EGMs.
3.
The JWG
conducts evaluation of new global EGMs.
5.
The JWG
encourages active participation and contribution from its members through email
contact, conferences/meetings, scientific presentations and publications.
6.
A WWW
site will be created to facilitate communication, information and data
exchanges.
The Joint
Working Group reports to IGFS and the Commission 2.
Membership:
Dr. Hussein Abd-Elmotaal, Minia University, Egypt
Dr. Min Kang
Cheng, CSR, University of Texas & Austin, USA
Dr. Gleb Demianov, Agency of Geodesy and Cartography, Ministry of Transport, Russia
Dr. Heiner
Denker, University of Hannover, Germany
Prof. Will
Featherstone, Curtin University of Technology, Australia
Dr.
Rene Forsberg, National Space Centre, Denmark
Dr. Thomas Gruber, IAPG, TUM, Germany
Dr. Jianliang
Huang, Geodetic Survey Division, CCRS, NRcan, Canada
Dr. Jaroslav Klokočníc , Astronomical
Institute of the Acad. of Sciences, Czech Republic
Dr.
Christopher Kotsakis, Aristotle University of Thessaloniki, Greece
Prof.
Jiancheng Li, Wuhan University, P. R. China
Prof. Charles
Merry, University of Cape Town, South Africa
Prof. Phil Moore,
Newcastle University, UK
Dr. Pavel Novák, Research Institute of
Geodesy, Czech Republic
Dr. Niko K
Pavlis, Raytheon ITSS Corporation, USA
Dr. Dan Roman,
National Geodetic Survey, USA
Correspondence:
Dr. S. Bettadpur, CSR, University of Texas & Austin, USA
Prof. C. Jekeli, The Ohio State University, USA
Mr. S. C.
Kenyon, National Geospatial-Intelligence Agency, USA
Prof. Ch. Reigber, GeoForschungsZentrum, Potsdam, Germany
Dr. J. Ries,
CSR, University of Texas & Austin, USA
Prof. R.
Rummel, IAPG, TUM, Germany
Prof. M.G.
Sideris, University of Calgary, Canada
Dr. N. Sneeuw,
University of Calgary, Canada
Prof.. B.D.
Tapley, CSR, University of Texas & Austin, USA
Dr. C. C. Tscherning, University of Copenhagen, Denmark
Prof. I.N.
Tziavos, Aristotle University of Thessaloniki, Greece
Mr. M.
Véronneau, Geodetic Survey Division, CCRS, NRCan, Canada
Dr. P. Visser,
Delft University of Technology, The Netherlands