Record details

Title
    Earth's dimension specified by geoidal geopotential
Statement of responsibility
    Milan Burša, Erwin Groten, Steve Kenyon, Jan Kouba, Karel Raděj, Viliam Vatrt, Marie Vojtíšková
Author
    Burša, Milan, 1929-
    Groten, Erwin
    Kenyon, Steve
    Kouba, Jan
    Raděj, Karel
    Vatrt, Viliam
    Vojtíšková, Marie
Language
    anglicky
Source title - serial
    Studia geophysica et geodaetica
Vol./nr.
    Vol. 46, no. 1
Pages
    p. 1-8
Year
    2002
Notes
    1 diagr., 1 tab.
    il.
    Obsahuje bibliografické odkazy
    Zkr. název ser.: Stud. geophys. geod. (Praha)
Classfication no.
    528
    55
    550.3
Conspectus category
    528
    55
Subject group
    geodézie
    geoid
    metody satelitové
    planeta Země
    světový výškový systém
    tvar Země
Geographical name
    Země
Keyword
    Dimension
    Earth's
    Geoidal
    Geopotential
    Specified
Abstract (in english)
   The TOPEX/POSEIDON (T/P) satellite altimeter data from January 1, 1993 to January 3, 200J (cycles 11 - 305) was used for investigating the long-term variations of the geoidal geopotential W0 and the geopotential scale factor R0 = GM/V/0 (GM is the adopted geocentric gravitational constant). The mean values over the whole period covered are W0 = (62 636 856.161+-0.002) mV2, R0 = (6 363 672.5448+-0.0002) m. The actual accuracy is limited by the altimeter calibration error (2 - 3cm) and it is conservatively estimated to be about+-0.5 m2s-2 (+-5 cm). The differences between the yearly mean sea surface (MSS) levels, came out as follows: 1993 -1994: -(1.2+-0.7) mm, 1994-1995: (0.5+-0.7) mm, 1995-1996: (0.5 +-0.7) mm, 1996-1997: (0.1+-0.7) mm, 1997-1998: -(0.5+-0.7) mm, 1998-1999: (0.0+-0.7) mm and 1999- 2000: (0.6+-0.7) mm. The corresponding rate of change in the MSS level (or R0) during the whole period of 1993 - 2000 is (0.02+-0.07) mm/y.
   The value W0 was found to be quite stable, it depends only on the adopted GM, w and the volume enclosed by surface W= W0. W0 can also uniquely define the reference (geoidal) surface that is required for a number of applications, including World Height System and General Relativity in precise time keeping and time definitions, that is why W0 is considered to be suitable for adoption as a primary astrogeodetic parameter. Furthermore, W0 provides a scale parameter for the Earth that is independent of the tidal reference system. After adopting a value for W0, the semi-major axis a of the Earth's general ellipsoid can easily be derived. However, an a priori condition should be posed first. Two conditions have been examined, namely an ellipsoid with the corresponding geopotential which fits best W0 in the least squares sense and an ellipsoid which has the global geopotential average equal to W0.
   It is demonstrated that both a-values are practically equal to the value obtained by the Pizzetti's theory of the level ellipsoid: a =(6 378 136.7+- 0.05) in
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    28. 3. 2008
Import date
    8. 8. 2012