Maximum cloud-to-ground lightning densities on Earth as observed by lightning location systems

摘要

Lightning Location Systems (LLS) to detect cloud-to-ground (CG) lightning flashes have been used in more than 40 countries around the World for many different applications. While their information has been proved very useful for operational users in different areas like forestry, electric utility industry, insurance industry, and general meteorological and aviation needs, their use in the characterization of CG lightning flash density in different regions on Earth has been limited by local variations in the LLS performance. To overcome this limitation different lightning detection efficiency models have been developed. However, at the present time these models have been validated by independent lightning observations only partially and in a few regions. In addition, values of the lightning flash density are subject to the influence of the contamination by intracloud flashes, misclassified as CG flashes, and are very sensitive to the spatial resolution adopted in their calculation. In this article, all these aspects were taking into account in order to compare maximum CG lightning flash densities obtained by different LLS in different countries. Only values corresponding to regions inside the boundaries of the networks were considered, due to the long-standing fall-off of the network performance outside these boundaries. It was found that maximum CG lightning flash densities observed by the different LLS in different countries, normalized to 1x1 km 2 resolution, vary from less than one to almost 70 flashes km -2 year -1 , in response to processes involving different meteorological systems and their interaction with different geographical features. Comparison of the values obtained in the tropical and temperate regions confirms that higher CG lightning flash density values on Earth are achieved in the tropics.