EGU2020-680
https://doi.org/10.5194/egusphere-egu2020-680
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Vertical Gravity Gradient Modeling by 3-D Least Squares Collocation and its impact on quasigeoid-geoid separation term

Gonca Ahi2, Yunus Aytaç Akdoğan1, and Hasan Yıldız1
Gonca Ahi et al.
  • 1General Directorate of Mapping, Geodesy Department, 06590, Ankara, Turkey
  • 2University of Hacettepe, Department of Geomatics Engineering, 06800, Ankara, Turkey

For the quasi-geoid determination by 3-D Least Squares Collocation (LSC) in the context of Molodensky’s approach, there is no need to measured or modelled vertical gravity gradient (VGG) as the 3-D LSC takes the varying heights of the gravity observation points into account. However, the use of measured or modelled VGG instead of the thereotical value is expected to improve the quasigeoid-geoid separation term particularly in mountainous areas. The VGG measurements are found to be different from the theoretical value in the range of - % 25 and + % 39 in western Turkey. Previously there has been no study using modelled VGGs for gravimetric geoid modelling in Turkey. VGGs are modelled by 3-D Least Squares Collocation (LSC) in remove-restore approach and validated by terrestrial VGG measurements in western Turkey. The effect of using modelled VGG instead of the theoretical one in quasigeoid-to-geoid separation term is found to be significant. The quasi-geoid computed by 3-D LSC in western Turkey is converted to geoids using theoretical or modelled VGG values and compared with GPS/levelling geoid-undulations.

 

How to cite: Ahi, G., Akdoğan, Y. A., and Yıldız, H.: Vertical Gravity Gradient Modeling by 3-D Least Squares Collocation and its impact on quasigeoid-geoid separation term , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-680, https://doi.org/10.5194/egusphere-egu2020-680, 2019