Variability in ionospheric total electron content at Mars

For regional studies, high resolution latitude patterns of variability in the southern hemisphere - within the longitude sector 150-210° of strong crustal-B values - were computed as percentage changes with respect to zonally-averaged patterns outside the region of interest. We present evidence for the first time of B-fields affecting the variability of the daytime ionosphere by small amounts (~±5%). Under nighttime conditions, the B-field associated variability is ~±20%. The results also reveal an anti-correlation between daytime and nighttime variability ordered by the inclination angle (I) of the B-fields. TEC variability is greater as I approaches vertical at night, but higher during the day (by smaller amounts) where I approaches horizontal patterns.