@Article{PoelmanSPCMHSH:2021:AlVa,
               author = "Poelman, Dieter R. and Schulz, Wolfgang and Pedeboy, Stephanie and 
                         Campos, Leandro. Z. S. and Matsui, Michihiro and Hill, Dustin and 
                         Saba, Marcelo Magalh{\~a}es Fares and Hunt, Hugh",
          affiliation = "{Royal Meteorological Institute of Belgium} and {Austrian 
                         Lightning Detection and Information System (ALDIS)} and 
                         {M{'e}t{'e}orage} and {Campos Scientific Computing} and 
                         {Franklin Japan Corporation} and {Scientific Lightning Solutions 
                         LLC (SLS)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} 
                         and {University of Witwatersrand}",
                title = "Global ground strike point characteristics in negative downward 
                         lightning flashes – Part 2: Algorithm validation",
              journal = "Natural Hazards and Earth System Sciences",
                 year = "2021",
               volume = "21",
                pages = "1921--1933",
                month = "Jun",
             abstract = "At present the lightning flash density is a key input parameter 
                         for assessing the risk of occurrence of a lightning strike in a 
                         particular region of interest. Since it is known that flashes tend 
                         to have more than one ground termination point on average, the use 
                         of ground strike point densities as opposed to flash densities is 
                         more appropriate. Lightning location systems (LLSs) do not 
                         directly provide ground strike point densities. However, ingesting 
                         their observations into an algorithm that groups strokes into 
                         respective ground strike points results in the sought-after 
                         density value. The aim of this study is to assess the ability of 
                         three distinct ground strike point algorithms to correctly 
                         determine the observed ground-truth strike points. The output of 
                         the algorithms is tested against a large set of ground-truth 
                         observations taken from different regions around the world, 
                         including Austria, Brazil, France, Spain, South Africa and the 
                         United States of America. These observations are linked to the 
                         observations made by a local LLS in order to retrieve the 
                         necessary parameters of each lightning discharge, which serve as 
                         input for the algorithms. Median values of the separation distance 
                         between the first stroke in the flash and subsequent ground strike 
                         points are found to vary between 1.3 and 2.75\ĝ¯km. It 
                         follows that all three of the algorithms perform well, with 
                         success rates of up to about 90\ĝ¯% to retrieve the correct 
                         type of the strokes in the flash, i.e., whether the stroke creates 
                         a new termination point or follows a pre-existing channel. The 
                         most important factor that influences the algorithms' performance 
                         is the accuracy by which the strokes are located by the LLS. 
                         Additionally, it is shown that the strokes' peak current plays an 
                         important role, whereby strokes with a larger absolute peak 
                         current have a higher probability of being correctly classified 
                         compared to the weaker strokes.",
                  doi = "10.5194/nhess-21-1921-2021",
                  url = "http://dx.doi.org/10.5194/nhess-21-1921-2021",
                 issn = "1684-9981",
             language = "en",
           targetfile = "poelman_global2.pdf",
        urlaccessdate = "09 maio 2024"
}