Abstract:
The response of the ionosphere to 26 December 2019 solar eclipse on the equatorial and low
latitude ionosphere has been investigated using ground and space based observations. The high
resolution Ionosonde observations at Tirunelveli, GPS TEC observations from a chain of GPS
receivers along and across the eclipse path, TIMED-SABER and lonospheric connection
explorer (ICON) satellites were utilized to investigate the eclipse induced variations in electron
density and thermospheric cooling. Tremendous increase in bottom side altitude of F-region
resembling Pre-Reversal Enhancement (PRE) was observed. Near eclipse maximum, strong
blanketing sporadic E layer was observed at Tirunelveli with top frequency 18MHz for 1 hour 26
minutes. Additional ionogram traces known as satellite traces (ST) and ‘U’ shaped ionograms
were noticed for the first time over Tirunelveli during eclipse maximum and eclipse ending
respectively. Presence of ‘ST’ and ‘U’ shaped traces in the ionograms indicate the short period
gravity waves or TID type of wave perturbations over Indian region. A maximum of ~5 TECU
decrease in TEC is observed on the eclipse day. Periodogram analyses of TEC data showed the
presence of wavelike structures with periodicities of 18-24 min for different stations.
Simultaneous observations from ICON satellite showed increase and decrease in hmF2 and
NmF2 which matches well with ionosonde at Tirunelveli respectively. The temperature profiles
from TIMED-SABER and ICON satellites showed a reduction and enhancement in the lower
and upper E region respectively during eclipse.
