Ionospheric Behavior During the Solar Eclipse of 22 July 2009 and Its Effect on Positioning

Abstract

On Jul. 22nd, 2009, an exceptionally long total solar eclipse was visible within a narrow corridor that traversed the Eastern Hemisphere. A medium geomagnetic storm synchronized with solar eclipse and led to the complexity of the ionospheric variations. This work is to analyze the ionospheric behavior during this event and its effect on positioning. The used GPS data were collected by the Chongqing CORS, Wuhan CORS, IGS stations such as WUHN and SHAO in Moon's umbra, and other IGS stations in Moon's penumbra. By comparing the TEC variations of 3 consecutive days, and using high-sampling rate CORS data, we study instantaneous changes of the total electron content (TEC) during the event. The result shows that TEC declined by (1∼4)TECU at places depending on different locations and times. Meanwhile, in real time point positioning, horizontal accuracy didn't have remarkable changes, but vertical accuracy declined up to several meters. And in real time baseline positioning, horizontal accuracy still reached centimeter level, and vertical accuracy remained at decimeter level in the early stage of solar eclipse. But the geomagnetic storm occurred in the latter stage of solar eclipse that led to the decline of horizontal accuracy to decimeter, and vertical accuracy to meter level.

GPS observations of ionospheric TEC variations over Nepal during 22 July 2009 solar eclipse

“…As a consequence, the findings presented here are essentially unaffected by the July 22 geomagnetic storm. This validates the previous findings [22,30].…”

“…So, the beginning time of the magnetic storm lagged behind the solar eclipse, and the magnetic storm faded away gradually in several hours after the ending of the eclipse. Thus, unlike solar eclipses in the past, which often have been followed by no magnetic storm, solar eclipse and magnetic storm synchronism characterized this eclipse [30]. The detailed study of TEC variation during geomagnetic storms is leaved for future work.…”

Tracking the Ionospheric Response to the Solar Eclipse of November 03, 2013

“…This is a clear manifestation of the direct dependence of electron production on photoionization process. The solar eclipse of July 22, 2009, was again studied by [13]. The authors investigated the behaviour of the ionosphere by measuring the variation in TEC for three (pre-, post-, and eclipse) consecutive days.…”

Ionospheric Behavior during the 10 June 2021 Annular Solar Eclipse and Its Impact on GNSS Precise Point Positioning

“…Few authors have analyzed the GNSS positioning errors caused by the influence of solar eclipses. The eclipses that occurred over Croatia on 11 August 1999 [27], over China on 22 July 2009 [28], and over the United States on 21 August 2017 [26] are some of the studies that analyzed GNSS positioning errors.…”

“…Jia-Chun et al [28] used eight GPS stations to study the TEC changes and their effect on the positioning during the 22 July 2009 solar eclipse. They possessed a real-time point positioning and real-time precision of single baselines.…”