Indian gravimetric geoid model using the Stokes-Helmert method: IndGG-SH2021
Abstract
This study presents the nationwide results of Indian gravimetric geoid and quasigeoid models computed using the Stokes-Helmert method with Vaníček-Kleusberg modification of the Stokes kernel. We have computed both geoid and quasigeoid models to analyse their representativeness of the Indian normal-orthometric heights from differential levelling. The geoid-quasigeoid separation term was computed using Flury and Rummel's (2009) formula. Free-air gravity anomalies over India were found to range from -300 mGal to +513 mGal, the Direct Topographical Effect ranges from -113 mGal to +341 mGal, the Primary Indirect Topographical Effect from -3.232 m to -0.012 m, and the geoid-quasigeoid separation from -0.733 m to +4.002 m. On validating IndGG-SH2021 with the whole of India GNSS/levelling dataset, the least standard deviation of ±0.46 m is achieved for the modification degree of 40 and integration radius of 1.5°. However, on region-wise GNSS/levelling validation, the least standard deviation varies from ±0.18 m in Uttar Pradesh West, ±0.09 m in Uttar Pradesh East, ±0.15 m in Hyderabad to ±0.03 m in Bangalore. In each region, different optimal kernel modification parameters were found, with the optimal modification degree ranging from 40 to 240 and the optimal integration radius from 0.2° to 2.0°.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.G42C0244G