Residual Terrain Model Effect and Gravimetric Terrain Correction for Gravity Field Modeling over Ethiopia
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Date
2022-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
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.
Description
Keywords
Gravity, RTM Effects, High-frequency, Terrain Corrections