Downward continuation and prediction of GOCE gravitational gradients
NOVÁK, P., SEBERA, J., ŠPRLÁK, M., VALKO, M., HAAGMANS, R. Downward continuation and prediction of GOCE gravitational gradients. Potsdam, SRN, 2013.
|Anglický název:||Downward continuation and prediction of GOCE gravitational gradients|
|Autoři:||Prof. Ing. Pavel Novák Ph.D. , Ing. Josef Sebera PhD. , Ing. Michal Šprlák Ph.D. , Miloš Valko Ph.D. , Roger Haagmans Ph.D.|
|Abstrakt EN:||Within the ESA?s STSE Theme 2 project, gravitational gradients observed by the GOCE gradiometer are applied to constrain geophysical models over two distinct geographic areas (the mid-ocean Reykjanes ridge and the sediment basin of the Congo River). This contribution describes derivation of equiangular coordinate grids of the gravitational gradients at mean satellite and ground levels. The downward continuation of the GOCE gravitational gradients in the terrestrial reference frame consists of two distinct steps: 1- gravitational gradients are projected onto a mean orbital sphere where they are predicted onto the equiangular coordinate grids; and 2- gridded gravitational gradients are continued downward by an iterative approach based on the Poisson integral equation. The continued values are tested against recent global geopotential models and their accuracy is estimated. Moreover, differences between gridded values of the gravitational gradients at different levels and gravitational gradients synthesized from state-of-the-art global geopotential models are analyzed over several geographic areas and at different altitudes above the Earth?s surface with the purpose of seeking signals not captured by the global geopotential models. Outcomes of the study show that 1- satellite gravitational gradients can be downward continued with the high relative accuracy; and 2- gridded gradients at different levels predicted from observed data may be beneficial for geophysical studies.|