author = "Mattos, Enrique Vieira and Machado, Luiz Augusto Toledo and 
                         Williams, Earle R. and Goodman, Steven J. and Blakeslee, Richard 
                         J. and Bailey, Jeffrey C.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Massachusetts 
                         Institute of Technology} and {NOAA/NESDIS/GOES-RProgram Office} 
                         and {NASA Marshall Space Flight Center} and {University of Alabama 
                         in Huntsville}",
                title = "Electri\fication life cycle of incipient thunderstorms",
              journal = "Journal of Geophysical Research: Atmospheres",
                 year = "2017",
               volume = "122",
               number = "8",
                pages = "4670--4697",
                month = "Apr.",
             keywords = "dual-polarization radar, first cloud-to-ground lightning flash, 
                         first radar echo, graupel, Lightning Localization System, 
                         supercooled raindrops.",
             abstract = "This work evaluates how clouds evolve to thunderstorms in terms of 
                         microphysical characteristics to produce the first intracloud (IC) 
                         and cloud-to-ground (CG) lightning flashes. Observations of 46 
                         compact isolated thunderstorms during the 2011/2012 spring-summer 
                         in Southeast Brazil with an X-band polarimetric radar and two- and 
                         three-dimensional Lightning Location Systems demonstrated key 
                         parameters in a cloud's vertical structure that produce the 
                         initial electrification and lightning activity. The majority (98%) 
                         of the first CG flashes were preceded (by approximately 6 min) by 
                         intracloud (IC) lightning. The most important aspect of the 
                         observations going into this paper, which came originally from the 
                         visual examination of a large number of thunderstorms, is that an 
                         initial positive differential reflectivity (ZDR) (associated with 
                         supercooled raindrops) evolved to reduced ZDR (and even negative 
                         values) in the cloud layer between 0 and to \−15C before 
                         and during the time of the initial lightning, suggesting evolution 
                         from supercooled raindrops to frozen particles promoting the 
                         formation of conical graupel. An enhanced negative specific 
                         differential phase (KDP) (down to \−0.5 km\−1) in 
                         the glaciated layer (above \−40C) was predominantly 
                         observed at the time of the first CG flash, indicating that ice 
                         crystals, such as plates and columns, were being vertically 
                         aligned by a strong electric field. These results demonstrate that 
                         the observations of ZDR evolution in the mixed layer and negative 
                         KDP in the upper levels of convective cores may provide useful 
                         information on thunderstorm vigor and lightning nowcasting.",
                  doi = "10.1002/2016JD025772",
                  url = "http://dx.doi.org/10.1002/2016JD025772",
                 issn = "2169-8996 and 2169-897X",
             language = "en",
           targetfile = "mattos_electrification.pdf",
        urlaccessdate = "25 nov. 2020"