author = "Bourscheidt, Vandoir and Pinto J{\'u}nior, Osmar and Naccarato, 
                         Kleber Pinheiro",
          affiliation = "{Universidade Federal de S{\~a}o Carlos (UFSCAR)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "The effects of Sao Paulo urban heat island on lightning activity: 
                         Decadal analysis (1999-2009)",
              journal = "Journal of Geophysical Research: Atmospheres",
                 year = "2016",
               volume = "121",
               number = "9",
                pages = "4429--4442",
                month = "May",
             keywords = "lightning activity, Sao Paulo, temperature contrast, thunderstorm 
                         initiation, urban heat islands.",
             abstract = "Eleven years of lightning data from the Brazilian Integrated 
                         National Lightning Detection Network were used to analyze the 
                         effects of the urban heat island (UHI) of Sao Paulo on lightning 
                         activity, extending the investigation of previous works. 
                         Cloud-To-ground lightning data were analyzed in both spatial and 
                         temporal perspectives, using different approaches: flash density, 
                         flash rate, thunderstorm hours (TH), and the cell initiation 
                         technique (CIT), which aims to identify the onset of 
                         thunderstorms. Land surface temperature (LST) from MODIS (Moderate 
                         Resolution Imaging Spectroradiometer) was used to analyze the UHI 
                         evolution over the years. MODIS data were validated using ground 
                         stations, distributed within the urban area. Different time 
                         intervals (seasonal and intraday) were used in an attempt to 
                         separate local convective systems from synoptic-scale events. The 
                         results indicate significant effects of the UHI (using LST) on THs 
                         and CIT. The CIT showed a nearly ring pattern, especially during 
                         the afternoon (14:00-18:00 LT) of summer months, reinforcing 
                         temperature contrast as a condition for storm initiation. The 
                         results also suggest an amplification of the UHI effects on 
                         thunderstorm activity by local factors (sea and country breeze, 
                         synoptic events, and terrain). Higher flash rates were also 
                         observed throughout the urban region, which influences the 
                         lightning density. Temporal analysis indicates that minimum 
                         temperature and lightning activity increase in wintertime. In 
                         summary, the results agree with previous studies about the UHI and 
                         indicate its importance on lightning occurrence, especially by 
                         increasing the temperature contrast and the instability in these 
                  doi = "10.1002/2016JD024782",
                  url = "http://dx.doi.org/10.1002/2016JD024782",
                 issn = "2169-8996 and 2169-897X",
             language = "en",
           targetfile = "bourscheidt_theeffects.pdf",
        urlaccessdate = "04 dez. 2020"