LAUSR

Abstract An analysis of vertical total electron content (TEC) estimates from the MIT Madrigal database is performed for the regions surrounding the eye of Hurricane Michael (2018). Absolute and detrended TEC values show a noticeable increase during the tropical cyclone (TC) relative to fluctuations at the same locations prior to the storm. Direct comparisons of TEC perturbation magnitudes to the number of lightning flashes in 1 ° × 1 ° latitude-longitude boxes surrounding the eye of Hurricane Michael for each 5 min period of 10 October 2018 showed no visible trends. A similar comparison of the vertical TEC fluctuations with respect to the rainfall rates showed a positive correlation as the rainfall rate increased from light to moderate. However, a decrease in TEC perturbations were observed for the most intense rainfall rates. Additionally, ionosonde measurements in the Gulf of Mexico Region reveal an increased production of waves with periods less than 90 min after TC formation. These results indicate that the measured TEC fluctuations are most likely caused by atmospheric gravity waves produced by Hurricane Michael, which supports previous research.