Testing Airborne Gravity Data in the Large-Scale Area of Italy and Adjacent Seas

Abstract

In 2012 the GEOHALO flight mission was carried out using the new German research aircraft HALO. The surveyed zone covers the Central-South part of Italy, roughly from latitude 36°N to 44°N. In this area, seven main tracks NW to SE were surveyed having a spacing of about 40 km and an altitude of 3,500 m, complemented by an eighth track in an altitude of 10,000 m. Four perpendicular cross tracks were also added.

Amongst the geodetic-geophysical equipment GEOHALO carried two gravimeters. In this paper we will focus on the GFZ instrument, a CHEKAN-AM gravimeter. The present investigation aims at defining the spectral properties and the level of precision of the observed gravity data. Comparisons with gravity anomalies predicted from Italian ground data are presented. The gravity field in the surveyed area as derived from these ground data is propagated to the aerogravimetry survey points and compared to the observed gravity anomalies. Upward continuation is performed using the remove-restore approach and collocation. High-resolution global geopotential models are compared with the observed data as well. The statistics of the gravity residuals show that the survey data fit the predicted gravity at 2–3 mGal standard deviation level which proves that a good standard has been reached. A trackwise analysis is also performed to check for possible local discrepancies between observed and predicted gravity.