Thunderstorm Essay

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A thunderstorm that produces large amounts of precipitation which reaches the ground should have deep moisture stratums in unstable conditions, causing enough convection to be restricted to the electrification level of the atmosphere, or being lifted by orographic or frontal systems (Rorig and Ferguson, 1999). However, some thunderstorms produce small amounts of precipitation or none. Colson (1960) explained this phenomenon as a result of high-level thunderstorms with high cloud bases where the appropriate conditions for triggering lightning flashes accompanied by precipitation are situated in the upper levels. Rorig and Ferguson (1999) analysed the synoptic patterns of dry thunderstorms and concluded that low moisture levels in the inferior part of the atmosphere coupled with high instability, leads to the evaporation of precipitation prior to reaching the ground level, this way reducing the moisture content of the underlying surface.
As a result, in many areas of the world, dry thunderstorms cause lightning-induced fires, and many authors have found this relationship suitable for quantitative investigation (Hall, 2005; Rorig and Ferguson, 2002). Hall (2005) investigated 15000 wildfires correlated with the total number of CG lightings that occurred from 1990 to 1998 in Arizona and New Mexico using precipitation data derived from historical gauge data. His results show that 75% of wildfires were initiated when there was zero precipitation, thus the source of ignition was attributed to dry lightning. Based on this study, a percentage of 0.0026 (112.5 CG) of the total CG lightning over a 9-year period accounting for dry lightning was derived. However, this number accounts for only a portion of the dry lightning, namely the ones th...

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... input parameters, efficiency of the lightning detection system and the observation period (Smorgonskiy et al.,2013). They proposed two new methods, namely, a gradient-based method and a subarea decomposition method, which provided positive results for the direct proportionality of elevation with lightning density even for altitudes above 1500 m across Switzerland and Austria. These results generally coincided with Schulz’s and Diendorfer’s (1999) study in Austria. As opposed to the findings of Smorgonskiy et al. (2013), Schulz and Diendorfer (1999) focused on a smaller area where the lightning location system had the best performance, and they overlapped it with elevations given by the GLOBE digital elevation model. They discovered that after an increase in flash density with altitude, beyond 2000, the flash density starts decreasing due to proximity of cloud bases.

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