تعيين ژنوييد محلي با استفاده از داده هاي مرزي حاصل از ثقل سنجي و ارتفاع سنجي ماهواره اي مطالعه خاص :ژنوييد دقيق ايران

Local Geoid Computations Based On Boundary Data Of The Type Gravity Intensity And Satellite Altimetry, Case Study: High-Resolution Geoid Of Iran

In this paper Abel-Poisson boundary value problem with boundary data of the type gravity intensity (from gravimetry) and sea surface height (from satellite altimetry) as a solution to geoid computation problem is presented. This method besides its high accuracy from its theoretical point of view, addresses the problem of high-accuracy geoid computations in the coastal areas. The highlights of the method are: - Application of ellipsoidal harmonic expansion up to degree/order 360 / 360 and ellipsoidal centrifugal field for the removal of the effect of global gravity and isostasy field from the gravity intensity observations at the surface of the earth. - Application of ellipsoidal Newton integral on the multi-cylindrical equal area map projection surface for the removal of the residual mass effects within a radius of 55 km around the computational point from the gravity intensity and astronomical observations at the surface of the earth. -Application of ellipsoidal harmonic expansion up to degree/order 360 / 360 and ellipsoidal centrifugal field for the removal of the effect of global gravity and isostasy on the geoidal undulations from the geoidal undulations derived from satellite altimetry. - Application of ellipsoidal Newton integral on the multi-cylindrical equal area map projection surface for the removal of the effect of the water masses outside the reference ellipsoid within a radius of 55 km around the computational point from the geoidal undulations derived from satellite altimetry. - Least squares solution of the observation equations of the incremental quantities derived from aforementioned stages in order to obtain the incremental gravity potential at the surface of reference ellipsoid. -Restore of the removed effects at the application points on the surface of reference ellipsoid. -Application of ellipsoidal Bruns formula for converting the potential values on the surface of the reference ellipsoid into the geoidal heights with respect to the reference ellipsoid. As the case study, computation of the high-resolution geoid of Iran based on gravity intensity and sea surface height from Topex-Posseidon satellite altimetry data is presented.