Mars ionosphere TEC estimation from MARSIS data: A new approach

We describe a new implementation of the Contrast Method (CM) algorithm ( Picardi and Sorge, 2000 ; Ilyushin Ya and Kunitsyn, 2004 ; Cartacci et al., 2013 ) used to correct the phase distortion of the echoes recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) ( Picardi et al., 2005 ; Jordan et al., 2009 ) in its subsurface mode. The New CM is designed following an improved approach which allows not only to perform its original task but also to estimate the Total Electron Content (TEC) of the Mars ionosphere with a better accuracy respect to the past ( Cartacci et al., 2013 ; Cartacci et al., 2017 ), in the nightside when the transmitted frequency is close to the ionosphere plasma frequency as well as in the dayside, thanks to a lesser use of theoretical approximations in the method development. Moreover, taking advantage of almost 16 years of MARSIS operations, corresponding to about 8700 orbits, we present an improved global map of the night side TEC variations due to the interaction with the Mars crustal magnetic field ( Safaeinili et al., 2007 ; Cartacci et al., 2013 ). • We proposed a new improved method to estimate the total electron content of Mars ionosphere. • We compare the total electron content of Mars ionosphere estimated with different models, analyzing the consistency and the validity of the obtained results. • We correlate the total electron content variation obtained during the night side with the new method with the crustal magnetic fields of Mars. • We produce distribution maps of the total electron content variation extending the coverage to the entire Mars.