Abstract
Abstract. The vertical coupling between the troposphere and the ionosphere presents some remarkable features. Under intense tropospheric convection, gravity waves may be generated, and once they reach the ionosphere, these waves may seed instabilities and spread F and equatorial plasma bubble events may take place. Additionally, there is a close association between severe tropospheric convection and lightning strikes. In this work an investigation covering an equinox period (September–October) during the deep solar minimum (2009) presents the relation between lightning strike activity and spread F (equatorial plasma bubble) detected over a low-latitude Brazilian region. The results show a considerable correlation between these two phenomena. The common element in the center of this conformity seems to be the gravity waves. Once gravity waves and lightning strikes share the same source (intense tropospheric convection) and the effects of such gravity waves in the ionosphere include the seeding of instabilities according to the gravity waves magnitude, the monitoring of the lightning strike activity seems to offer some information about the subsequent development of spread F over the equatorial region. Keywords. Ionosphere (equatorial ionosphere)
Highlights
We discuss the fundamental role of the prereversal enhancement of the vertical drift (PRVD) on the generation of spread-F–equatorial plasma bubble (EPB) structures
It is generally accepted that the lightning strike activity is closely related to severe tropospheric convection (Deierling and Petersen, 2008; Boccippio, 2001; Williams et al, 1989 and references therein)
Strong tropospheric convection is usually evoked to explain the generation of gravity waves (e.g., Li et al, 2016; Kherani et al, 2009, 2011, 2016; Dutta et al, 2009; Fritts et al, 2008; Hoke and Tsuda, 2001; Lane et al, 2001; Dewan et al, 1998; Taylor and Hapgood, 1988; Röttger, 1977, 1980, 1981)
Summary
In recent decades several studies have been performed exposing the role of the gravity waves (GWs) on the onset and development of F region instabilities such as spread-F and equatorial plasma bubble (EPB) structures (e.g., Kherani et al, 2009, 2011; Makela et al, 2010; Vadas and Fritts, 2009; Abdu et al, 2009a; Fritts et al, 2008; Abdu, 2001; Singh et al, 1997; Huang and Kelley, 1996a–d; Huang et al., 1993; Hysell et al, 1990; Röttger, 1982; Kelley et al, 1981). spread-F and EPB events depend, in general, on a favorable unstable background configuration and the action of a seeding mechanism. During the prereversal enhancement of the zonal electric field, the vertical drift increases abruptly Throughout this prereversal enhancement of the vertical drift (PRVD) the ionosphere is elevated and the critical parameters for the Rayleigh–Taylor instability (e.g., density gradient scale length and collision frequency) may suffer considerable modifications depending on the PRVD characteristics, in particular the value of the peak of the PRVD (Vpk). Under these conditions gravity waves reaching the ionosphere may act as a seed, triggering the instabilities which lead to the presence of spread-F and EPB structures. Based on these previous studies, one must expect a close relationship between lightning strike activity and the presence and generation of GW since both events share the same source
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
