“…The above microphysical effect, known as aerosol convective invigoration [Koren et al, 2005], results in a potential sensitivity of lightning and storm vertical development to human activities, which have perturbed CCN concentrations on regional and global scales [Boucher and Lohmann, 1995;Pierce et al, 2007;Merikanto et al, 2009;Dunne et al, 2016]. Aerosol invigoration of storms is found using computer models of cloud systems [Fan et al, 2013;Mansell and Ziegler, 2013;Altaratz et al, 2014;Rosenfeld et al, 2014;Wang et al, 2014;Zhao et al, 2014;Guo et al, 2016], and observations often show positive correlations between cloud top height, and/or the lightning flash rate with aerosol optical depth (AOD), a proxy for CCN [Andreae, 2004], or with below-cloud particle number concentrations [Andreae, 2004;Koren et al, 2005;Bell et al, 2008Bell et al, , 2009Khain et al, 2008;Altaratz et al, 2010;Yuan et al, 2011;Li et al, 2011;Heiblum et al, 2012;Wall et al, 2014;Storer et al, 2014;Stolz et al, 2015;Pattantyus and Businger, 2014].…”