“…This additional layer does not occur at middle and high latitudes. Several research groups have published interesting papers on the formation mechanism and short-and long-term variations of the F 3 layer (Balan et al, 1998(Balan et al, , 2000Batista et al, 2002;Fagundes et al, 2007;Lynn et al, 2000;Rama Rao et al, 2005;Sreeja et al, 2010;Tardelli et al, 2016Tardelli et al, , 2018Thampi et al, 2007;Uemoto et al, 2007Uemoto et al, , 2011Zain et al, 2008;Zhao et al, 2014). As proposed by Balan et al (1998), the F 3 layer occurs because of the combined effects of the upward E × B drift and magnetic meridional neutral wind together with the usual daytime photochemical and dynamical processes.…”