GPS TEC response to the 22 July 2009 total solar eclipse in East Asia

The eclipse was accompanied with a medium magnetic storm, whose main phase onset occurred ~27 min after the passage of the Moon's umbral shadow. Using TEC data from 60 GPS stations, we construct differential TEC maps to investigate the ionosphere response to the solar eclipse in central China in the range of 26°N–36°N, 108°E–118°E (i.e., the magnetic latitude 15°N–25°N).

During the eclipse's totality, a "shadow" in the ionosphere shown as TEC depletion area was formed ~100 km south of the Moon's umbral path with a maximum decrease of 5 TECU. The TEC depletion area moved eastward, following the movement of the totality area with a time lag of ~10 min. Enhancements of TEC due to the storm are observed after the main phase onset.