Low ionospheric reactions on tropical depressions prior hurricanes

TL;DR

This study investigates how the low ionosphere reacts to tropical depressions before hurricanes, revealing frequent ionospheric turbulence associated with these weather phenomena using VLF radio signals.

Contribution

It provides the first detailed analysis of low ionospheric reactions to tropical depressions prior to hurricane formation, using VLF signals over a large event sample.

Findings

88% of tropical depressions showed ionospheric turbulence

Similar reactions observed in non-hurricane tropical depressions

Perturbations more frequent in depressions that lead to hurricanes

Abstract

We study the reactions of the low ionosphere during tropical depressions (TDs) which have been detected before the hurricane appearances in the Atlantic Ocean. We explore 41 TD events using very low frequency (VLF) radio signals emitted by NAA transmitter located in the USA and recorded by VLF receiver located in Belgrade (Serbia). We found VLF signal deviations (caused ionospheric turbulence) in the case of 36 out of 41 TD events (88%). Additionally, we explore 27 TDs which have not been developed in hurricanes and found similar low ionospheric reactions. However, in the sample of 41 TDs which are followed by hurricanes the typical low ionosphere perturbations seem to be more frequent than other TDs.