Browsing by Author "Sadik, Shewmollo"

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    Residual Terrain Model Effect and Gravimetric Terrain Correction for Gravity Field Modeling over Ethiopia
    (Addis Ababa University, 2022-03) Sadik, Shewmollo; Tulu, Besha (PhD)
    In this study, residual terrain model effects and terrain corrections were computed at 1.5 arcminute grid nodes and terrestrial gravity stations and presented in grid maps having 1.5 arc minute spatial resolutions over Ethiopia. 30 arc second SRTM DEM was used in the construction of Residual Terrain Model elevation of d/o 200 and 2190. A smooth surface was observed in the mean elevation surface corresponding to ~100km spatial scale. The mean elevation surface computed from the low pass filter was adopted because it shows better spectral details than the topography spherical harmonic methods. The computations were made with an integration radius of 20km and 200km for inner and outer zones respectively. In Ethiopia, 92.12% of RTM direct effects corresponding to d/o 200 reaches 25mgal and 85.74% of RTM indirect effects are less than 30cm. 98.85% of terrain corrections are less than 15mgal. For reference surface corresponding to ~9km spatial scale, 97.52% of the RTM direct effects are less than 25mgal. 98.26% of indirect effects are less than 5cm. the RTM effects and terrain corrections computed with mean elevation surface corresponding to ~9km spatial scale are not significant. The result of the study can be applicable for accurately interpretation of geoscientific studies.