Comparative study of the far zones effect on the spherical downward continuation
PITOŇÁK, M., ŠPRLÁK, M., SEBERA, J., NOVÁK, P., HAMÁČKOVÁ, E. Comparative study of the far zones effect on the spherical downward continuation. Prague; Czech Republic, 2016.
|Anglický název:||Comparative study of the far zones effect on the spherical downward continuation|
|Autoři:||Ing. Martin Pitoňák Ph.D. , Ing. Michal Šprlák Ph.D. , Josef Sebera , Prof. Ing. Pavel Novák Ph.D. , Eliška Hamáčková|
|Abstrakt EN:||Downward continuation of the potential data is useful tool for manipulating and interpreting satellite gravity data near the generating sources. Several methods and strategies have been proposed for the downward continuation of the satellite gravity data. This contribution investigates regional recovery of the second radial derivative of the disturbing gravitational potential at the mean sphere in the area of Europe from the same quantity measured by satellite GOCE. A special attention is paid to far zone effects, which are estimated with three approaches. In the first approach, which will be a reference, we use a full (near global) coverage of GOCE-based measurements. In the second approach, the integral formula is rigorously decomposed into two parts, i.e., the effects of the second radial derivative of the disturbing gravitational potential within near and distant zones. While the effect of the near zone is sought as an inverse problem, the effect of the distant zone is synthesized from the global gravitational model GGM05S using spectral weights given by truncation error coefficients. In the third approach the effect of far zones is computed by the numerical integration with the same global gravitational model as in the previous approach. The process of the downward continuation is stabilized by the Tikhonov regularization. Estimated values of the radial-radial component of the disturbing gravitational tensor are compared with those that are synthesized directly from EGM2008.|