Gravity and geoid in the Mediterranean Sea: the GEOMED project

Abstract

The peculiar features of the Mediterranean Sea in terms of both gravity variations and geodynamic complexities resulted in a wide range of studies and research projects during the last decades focusing on the modeling of static and dynamic processes of this almost closed sea basin. The scope of the present study is twofold. The first part shall provide a synopsis of the data and methods used and the results achieved for geoid determination in the first phase of the GEOMED project (GEOid in the MEDiterranean) in the early 90s. The second part focuses on the recent activities and improvements of the continuation of the previous research in the framework of the GEOMED-2 project which is still an ongoing work. The collection of all available surface and satellite data towards the creation of improved gravity databases and the computation of marine geoid models are discussed. The crucial role of global geopotential models and digital topography and bathymetry is analyzed, focusing on the efficient modeling of the low and high frequencies of the gravity signal. The numerical methodology is discussed in the context of the available data sets and computer facilities over the duration of GEOMED. Finally, gravity databases and geoid models for the whole test area are presented and evaluated for both phases of the project. Some recommendations are also drawn along with a discussion on new methodological tools for the implementation of new data sources, targeting to the future improvement of gravity field over the Mediterranean Sea.