The Far-Away Effects of Solar Eclipse

We investigate ionospheric variations related to the total solar eclipse that occurred over the continental United States on 21 August 2017. Our study is focused on quantifying eclipse effects on spatial ionospheric variations associated with the eclipse. We use observations by Millstone Hill and Arecibo incoherent scatter radars to investigate ionospheric variations as a function of altitude, GNSS TEC observations to understand latitudinal extend of ionospheric variations, and NASA TIMED GUVI and SEE data for spatial variations of neutral composition and temperature as well as solar UV flux.

Previous studies have shown that the ionosphere’s response to solar eclipses has a distinct latitudinal dependence. The response of the low-latitude and equatorial ionosphere is more intense and may be quite different from the middle latitude ionosphere response. In addition, theoretical calculations show that when the eclipse takes place in the Northern Hemisphere, a small ionospheric disturbance also appeared in the conjugate hemisphere, indicating importance of dynamical processes. Simulations suggest that most of the observed differences in the behavior of NmF2 during eclipses (solar zenith angle, local time, and dip angle effects) can be attributed to differences in O+ loss rate related to background differences in neutral molecular densities. Our observations provide essential data to test these hypotheses and provide a comprehensive view of changes in the near-Earth space environment induced by solar eclipse.