Investigating the Efficacy of Global Digital Elevation Models in Regional Geoid Modelling for the Indian Region

The digital elevation model (DEM) plays a crucial role in remote sensing, providing several important applications and benefits, such as hydrological modelling, precision agriculture, geoid modelling, etc. With the evolution in GNSS over a period of time, procuring ellipsoidal height is easily achievable, but applications like hydrological modelling require physically meaningful height, i.e. orthometric height that be obtained from geoid modelling, which includes gravity data from aerial and satellite gravity missions (GOCE, GRACE-FO, etc.). DEMs serve as key inputs in the geoid modelling process and are critical for computing terrain correction and reduction of gravity anomalies. Therefore, this study aims to investigate the sensitivity of DEM in geoid modelling. This study utilizes the GRAVSOFT method for geoid development and assessment of popular DEMs, namely MERIT and SRTM. Elementary statistical analysis shows that the MERIT outperformed the SRTM DEM based on the observed RMSE between developed geoid and GNSS and precise levelling points.