Geoid from geopotential model in the Taiwan area

Abstract

The geoid undulation on GRS80 in the Taiwan area at half‐degree grid points has been calculated using the reduced 30’ × 30’ block mean gravity anomalies and the OSU91A geopotential coefficient set up to degree and order 360. The OSU91A results have been used to compare with WGS84, CEM10C, and OSU86F geoid undulations determined in 18 first‐order triangulation stations of the Taiwan Geodetic Datum 1980 (TGD80). Comparisons have also been made between these free‐air anomalies determined from OSU91A, and terrestrial gravity anomalies. It has been found that the average difference between the OSU91A model‐derived, and 243 actual point free‐air anomalies is 16.8 ± 48.0 mgal. It has also been found that more reliable and dense terrestrial gravity data are needed, both for terrestrial observations and for the OSU91A model, to achieve the very high‐precision geoid on GRS80 in the area of study.

Keywords:

• geopotential model
• WGS84
• GRS80
• OSU91A
• GEM10C
• OSU86F
• geoid
• gravity anomaly