Ionospheric Disturbances That Accompanied the Super Typhoon Lekima Event
of 4 - 12 August 2019
Abstract
We acquired measurements with the oblique HF Doppler technique in the
city of Harbin during the super typhoon Lekima event of 4 – 12 August
2019. The ionospheric response was observed by the Harbin Engineering
University multifrequency multiple path coherent radio system in the
People’s Republic of China. The maximum disturbance in the ionosphere
was observed to occur during the day when the super typhoon Lekima
energy gained a maximum value and when the super typhoon approached
close to the ionospheric part of the radio-wave propagation paths. The
magnitude of the ionospheric disturbances decreased with the distance
between the super typhoon and propagation path midpoints. Both aperiodic
(chaotic) and quasiperiodic disturbances were observed to accompany the
super typhoon action in the ionosphere. The periods of the quasiperiodic
disturbances were observed to be ~12 – 24 min. Such
periods pertain to atmospheric gravity waves. The atmospheric gravity
waves generated by the super typhoon gave rise to quasiperiodic
variations in the electron density with relative amplitudes of
~3% to ~19%.