Researchers from James Madison University conducted a comprehensive study of thunderstorm environments in two distinct geographic regions: Washington, DC, and the Kansas City metropolitan area.
Land cover and atmospheric boundary layer characteristics modify thunderstorms and their characteristic phenomenon: lightning.
The most intense thunderstorm contrasts on Earth occur along continental and oceanic boundaries.
Generally, lightning strikes land at an order of magnitude more than it strikes sea.
The thermodynamic properties of the atmosphere vary significantly with different land covers over the Earth’s surface.
“Pollutants act as cloud nuclei,” said Mace Bentley, a professor at James Madison University and lead author of the study.
“Updrafts carry them into the clouds, and the updrafts and downdrafts separate the polluting particles, dispersing the electrical charges in the clouds and encouraging lightning to form.”
For the study, the authors surveyed nearly 200,000 thunderstorm events in the Washington, DC, area and more than 300,000 in the Kansas City area.
Using 12 years of lightning data from the National Lightning Detection Network and data from hundreds of air pollution monitoring stations in two cities, they found that in highly volatile environments, increased pollution increases the frequency of anti-ground lightning strikes.
“Our analysis identified a total of 196,836 thunderstorm events in the Washington DC area, while 310,209 thunderstorms were identified from the Kansas City lightning database,” the researchers said.
“In Washington, DC and Kansas City, more than 37.7% and 39.2% of all thunderstorm events, respectively, consisted of 10 or more flashes.”
“Evidence suggests that thunderstorm environments during mild warm-season synoptic weather are substantially different in terms of thermodynamics, aerosol properties, and aerosol concentrations in the Washington, DC, and Kansas City regions,” the researchers added.
“However, thunderstorm intensity, as measured by flash counts, appears to be controlled by similar thermodynamic and aerosol relationships despite differences in the surrounding environments.”
“When we look at the environments in which thunderstorms occur, we find a statistically significant positive correlation between convective available potential energy and the number of lightning events.”
“Aerosol concentration also appears to be a more important quantity than particle size when it comes to lightning enhancement.”
Scientists are now conducting a similar study in Bangkok, Thailand, a megacity that is more polluted than Washington, DC, or Kansas City and sits in a hot, tropical climate.
The results so far are similar, but these storms are showing a higher incidence of lightning.
“It appears that urban pollution can enhance thunderstorms and lightning wherever you go in the world,” Prof Bentley said.
of study Published in a journal Atmospheric Research.
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Mace Bentley others2024. Towards elucidating the relationship between thunderstorms and aerosols: An observational study centered on Washington, DC and Kansas City, Missouri. Atmospheric Research 304: 107402; doi: 10.1016/j.atmosres.2024.107402
Source: www.sci.news
