Abstract
Abstract. The variability of ionospheric response to the total solar eclipse of 22 July 2009 has been studied analyzing the GPS data recorded at the four Indian low-latitude stations Varanasi (100% obscuration), Kanpur (95% obscuration), Hyderabad (84% obscuration) and Bangalore (72% obscuration). The retrieved ionospheric vertical total electron content (VTEC) shows a significant reduction (reflected by all PRNs (satellites) at all stations) with a maximum of 48% at Varanasi (PRN 14), which decreases to 30% at Bangalore (PRN 14). Data from PRN 31 show a maximum of 54% at Kanpur and 26% at Hyderabad. The maximum decrement in VTEC occurs some time (2–15 min) after the maximum obscuration. The reduction in VTEC compared to the quiet mean VTEC depends on latitude as well as longitude, which also depends on the location of the satellite with respect to the solar eclipse path. The amount of reduction in VTEC decreases as the present obscuration decreases, which is directly related to the electron production by the photoionization process. The analysis of electron density height profile derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere & Climate) satellite over the Indian region shows significant reduction from 100 km altitude up to 800 km altitude with a maximum of 48% at 360 km altitude. The oscillatory nature in total electron content data at all stations is observed with different wave periods lying between 40 and 120 min, which are attributed to gravity wave effects generated in the lower atmosphere during the total solar eclipse.
Highlights
vertical total electron content (VTEC)The background VTEC for the reference is obtained by averaging the VTEC values of 17, 18, 19, 20, 27, 28, and 31 July
In the same figure the average VTEC derived from the same PRN is plotted
In order to support our argument that the wavy structures present in difference in TEC (DTEC) are due to the solar eclipse, we considered quiet and non-eclipse day VTEC data, and a similar DTEC analysis is carried out
Summary
VTECThe background VTEC for the reference is obtained by averaging the VTEC values of 17, 18, 19, 20, 27, 28, and 31 July. There is maximum reduction in VTEC at Varanasi and Kanpur stations for PRN 14 at around 06:30 IST (India Standard Time) (i.e., after about 5 min from the maximum obscuration and 1 h from the beginning of the partial eclipse).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
