@Article{PoelmanSPHSHSVMSW:2021:GlGrSt,
               author = "Poelman, Dieter R. and Schulz, Wolfgang and Pedeboy, Stephanie and 
                         Hill, Dustin and Saba, Marcelo Magalh{\~a}es Fares and Hunt, Hugh 
                         and Schwalt, Lukas and Vergeiner, Christian and Mata, Carlos T. 
                         and Schumann, Carina and Warner, Tom",
          affiliation = "{Royal Meteorological Institute of Belgium} and {Austrian 
                         Lightning Detection and Information System (ALDIS)} and 
                         {M{'e}t{'e}orage} and {Scientific Lightning Solutions LLC (SLS)} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {University of Witwatersrand} and {Graz University of Technology} 
                         and {Graz University of Technology} and {Scientific Lightning 
                         Solutions LLC (SLS)} and {University of Witwatersrand} and {ZT 
                         Research}",
                title = "Global ground strike point characteristics in negative downward 
                         lightning flashes-Part 1: Observations",
              journal = "Natural Hazards and Earth System Sciences",
                 year = "2021",
               volume = "21",
               number = "6",
                pages = "1909--1919",
                month = "June",
             abstract = "Information about lightning properties is important in order to 
                         advance the current understanding of lightning, whereby the 
                         characteristics of ground strike points (GSPs) are in particular 
                         helpful to improving the risk estimation for lightning protection. 
                         Lightning properties of a total of 1174 negative downward 
                         lightning flashes are analyzed. The high-speed video recordings 
                         are taken in different regions, including Austria, Brazil, South 
                         Africa and the USA, and are analyzed in terms of flash 
                         multiplicity, duration, interstroke intervals and ground strike 
                         point properties. According to our knowledge this is the first 
                         simultaneous analysis of GSP properties in different regions of 
                         the world applying a common methodology. Although the results vary 
                         among the data sets, the analysis reveals that a third of the 
                         flashes are single-stroke events, while the overall mean number of 
                         strokes per flash equals 3.67. From the video imagery an average 
                         of 1.56 GSPs per flash is derived, with about 60% of the 
                         multiple-stroke flashes striking the ground in more than one 
                         place. It follows that a ground contact point is struck 2.35 times 
                         on average. Multiple-stroke flashes last on average 371ms, whereas 
                         the geometric mean (GM) interstroke interval value preceding 
                         strokes producing a new GSP is about 18% greater than the GM value 
                         preceding subsequent strokes following a pre-existing lightning 
                         channel. In addition, a positive correlation between the duration 
                         and multiplicity of the flash is presented. The characteristics of 
                         the subset of flashes exhibiting multiple GSPs is further 
                         examined. It follows that strokes with a stroke order of 2 create 
                         a new GSP in 60% of the cases, while this percentage quickly drops 
                         for higher-order strokes. Further, the possibility of forming a 
                         new lightning channel to ground in terms of the number of strokes 
                         that conditioned the previous lightning channel shows that 
                         approximately 88% developed after the occurrence of only one 
                         stroke. Investigating the time intervals in the other 12% of the 
                         cases when two or more strokes re-used the previous lightning 
                         channel showed that the average interstroke time interval 
                         preceding a new lightning channel is found to be more than twice 
                         the time difference between strokes that follow the previous 
                         lightning channel.",
                  doi = "10.5194/nhess-21-1909-2021",
                  url = "http://dx.doi.org/10.5194/nhess-21-1909-2021",
                 issn = "1684-9981",
             language = "en",
           targetfile = "poelman_global1.pdf",
        urlaccessdate = "20 maio 2024"
}