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Precipitation and Lightning Activity over Tropical Lakes
  • Hikari Fukuda,
  • Rachel Albrecht
Hikari Fukuda
University of Sao Paulo

Corresponding Author:hikari@usp.br

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Rachel Albrecht
University of Sao Paulo
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Abstract

Although the intensity and frequency of lightning and rainfall are higher over the continents and during the daytime, the place with the most lightning in the world is Lake Maracaibo, a tropical lake in Venezuela with nighttime thunderstorms. Lake Maracaibo is a very large and warm lake surrounded by Andes mountains, the perfect scenario for convergent windflow (mountain–valley, lake, and sea breezes) over the lake nearly year-round, contributing to nocturnal thunderstorm development over 290 days per year on average. Several other tropical lakes with similar physical features (e.g., large area and elevated topography nearby), also exhibit deep nocturnal convection driven by locally forced convergent flow. We use the 16 years of precipitation and lightning activity observed by the Tropical Rainfall Measuring Mission (TRMM) to study the relationship between the physical characteristics (size, shape, local topography and water temperature) of tropical lakes and the precipitation and lightning activity of their thunderstorms. We found that nearby elevated topography and the size of the lake are important for deepening the convection and for increasing the electrical activity, having local driven breeze circulations as one of the consequences. Our results also suggest a nearly linear relationship between the lake area and lightning activity over the lakes. Each water body presented different characteristics, however, on average they show more intense thunderstorms in the summer months and nighttime period (e.g., higher reflectivity values deeper in the cloud, lower minimum brightness temperature, higher convective precipitation volume).