Iberia-Azores Gravity Model (IAGRM) using multi-source gravity data

• Published in: Earth, Planets and Space
• Main Author: Catalao, J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2006
• Subjects: Space and Planetary Science; Geology; North East Atlantic
• Online Access: http://dx.doi.org/10.1186/bf03351924; https://link.springer.com/content/pdf/10.1186/BF03351924.pdf; https://link.springer.com/article/10.1186/BF03351924/fulltext.html; http://link.springer.com/content/pdf/10.1186/BF03351924

Abstract A consistent high precision and high resolution gravity model in the north-east Atlantic off Iberia peninsula using multi-source gravity data, ship-borne and satellite derived gravity anomalies, is presented. A solution strategy based on least squares optimal interpolation was used to assimilate into a coherent gravity model, gravity data with different spectral and spatial resolutions. Satellite derived gravity anomalies from KMS02 model, with an error covariance of 25 mGal 2 , and marine data carefully edited and validated by bias crossover error adjustment, were used in this study. The observation error variance was determined from ship-borne track adjustment and assigned an independent value for each track determined from error variance propagation. Unbiased ship-borne gravity observations were assimilated into the satellite derived gravity KMS02 model by the least squares optimal interpolation algorithm (OI) with bias removed by applying a regional bias to all ship tracks (OI-b) and alternatively by constraining all ship tracks to KMS02 using bias and tilt (OI-t). External error of the model was determined by comparing with recent surveys and it was verified that OI-t approach improved the final gravity model to an accuracy of about 3 mGal. The effect of different merging approaches on geoid solution was also evaluated and it was verified that the merging process can contribute to improve the geoid accuracy up to 4 cm with the OI-t approach.