GeoGravGOCE: A standalone MATLAB GUI for processing GOCE satellite gradient data

Abstract

The exploitation of data from the Global Ocean Circulation Explorer (GOCE) mission still offers unique insights in Earth system processes despite the fact that the mission has been completed more than eight years ago. The use of GOCE data requires tedious and cumbersome processing in order to extract them from their original format, process them in the various reference frames and filter them to derive final products at the orbital altitude. GeoGravGOCE is an open-source software, developed in MATLAB, which aims to provide a friendly Graphical User Interface (GUI) to process the original GOCE gradiometric observations, i.e., second-order derivatives of the gravitational potential as provided by the European Space Agency. It is composed of four main tabs, which first allows the GOCE gradient pre-processing and the transformation of gradients from a geopotential models to the gradiometric reference frame. Then, the spectral filtering and the mutual transformations of gravity gradients between the four reference systems used in satellite gravimetry can be carried out.. Three main filtering methods are implemented within the software, referring to: Finite Impulse Response (FIR), Infinite Impulse Response (IIR), and Wavelet Multi-Resolution Analysis (WL-MRA) filters. The user is free to select the desired degree of filtering and evaluate the derived results in terms of both the power spectral density of the filtered signals and their spatial distribution. The present work gives an analytical outline of the program, along with its various functionalities, while results derived from the processing of original GOCE data are presented as well. GeoGravGOCE is a free software under the GNU license and can be freely accessed via the project webpage http://olimpia.topo.auth.gr/GeoGravGOCE/.