engleski

Numerical investigation on the importance of digital elevation models in regional geoid modelling

Topographic masses are known to have a significant effect in regional geoid modeling. In fact, many authors have emphasized that short wavelengths filtering of gravity signal is crucial in recovering geoid undulations from gravity data. Digital elevation (DEM) and bathymetric models (DBM) are data sources for computation of topographic effects which are later applied on the input data. Vertical accuracy and resolution are two attributes of DEMs known to be especially important in computations. The issue prior to any calculation of topographic effects is how to create and select optimal DEM/DBM from a large number of possibilities, what is its minimal vertical accuracy and in which minimal resolution should it be given in order to successfuly develop geoid model. In this numerical experiment available global DEMs will be used in regional geoid modelling over few study areas worldwide. Prior to DEMs application in geoid modelling, their vertical accuracy will be validated. After DEM validation, geoid models will be computed using LSMSA/KTH approach in order to analyse the influence of DEMs on the accuracy of computed geoid models. Results shall provide insights on the importance of selecting DEM/DBM and their most important attributes in satisfying today's demands of 1-2 cm regional geoid models

digital elevation models ; geoid ; topographic effects ; resolution ; accuracy ; GNSS/levelling ;

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