Determinación del modelo geoidal regional con la técnica clásica stokes–helmert para el departamento del Valle Del Cauca Colombia

Abstract

This study presents the development of a regional geoidal model for the Valle del Cauca department (Colombia), calculated using the classical Stokes-Helmert technique. To accomplish this, terrestrial, aerial, and satellite gravimetric data were jointly integrated with a high-resolution digital elevation model, which allowed leveraging the complementary characteristics of the different information sources. The processing comprised an initial phase of organization, standardization, and rigorous purification of more than one million gravimetric observations from the different aforementioned sources, followed by the application of terrain correction and adjustment of gravity anomalies obtained from the gravimetric data, using the global model XGM2019e as reference, truncated to degree 630 and with local expansion up to degree 145. Likewise, the calculation was implemented in free scientific software, adapting the CSHSOFT package methodology (Abbak et al., 2024) to Python (GRAV_UD), which enabled implementing a more flexible and reproducible workflow. As a result, a geoid was obtained for the Valle del Cauca department using the Stokes-Helmert technique, which presented significant improvements in mountainous areas, where resolution and precision acquire greater relevance. Consequently, validation of the results against the global model confirmed that a regional geoid presents greater accuracy, since it incorporates local parameters that better capture gravimetric variability. In particular, the m0 parameter, which represents the root mean square of the differences between the calculated geoidal undulations and those of the reference model, was reduced from 48.2 cm to 43.21 cm. This decrease indicates an improvement in concordance with physical reality, especially in mountainous areas, where geoidal undulation shows abrupt variations and model resolution acquires greater relevance.