A study of the long‐term variability of thunderstorm days in southeast Brazil

Abstract

In this report thunderstorm day monthly records obtained in three cities of southeast Brazil (São Paulo, Campinas, and Rio de Janeiro) since the 19th century are analyzed. The analysis is complemented by the spatial distribution of lightning in the last decade. For São Paulo and Campinas, data indicate a significant increase in thunderstorm activity during the period from the end of the 19th century to the present, simultaneously to an increase in the surface temperature well correlated to the population growth of the cities. This result did not match anything expected from natural climate cycles and gives strong observational evidence for the anthropogenic influence on the thunderstorm activity. For Rio de Janeiro, data did not show a significant positive trend from the middle of the 19th century to the present in spite of the increase in the surface temperature, suggesting that variations are most probably a result of a complex combination of local and large‐scale features. In addition, a statistical analysis of the data after 1951 shows that a significant increase (by a factor of 3.7) in the thunderstorm activity in Rio de Janeiro occurs for the simultaneous occurrence of a positive anomaly of the South Atlantic sea surface temperature and La Niña, compared to the simultaneous occurrence of a negative anomaly and El Niño, even though no significant variation was found when each large‐scale phenomena occurs isolated. The same occurs for São Paulo and Campinas, although with a lower amplitude.

Lightning NO x and Impacts on Air Quality

“…In addition, the percentage of positive-polarity flashes also generally decreases. Urbanization has also been implicated in driving temporal trends and variability in lightning observations over southeastern Brazil [121] and central and southeastern China [180,181].…”

Relationship between human observations of thunderstorms and the PERUN lightning detection network in Poland

“…Warm and cold air advections that differentiate air density may also in random cases affect propagation of sound (Changnon, 1993). These and other factors such as site-specific topography, fast growing cities that overbuild old stations and station relocations in turn may influence obtained annual average number of days with the thunderstorms over the particular stations and make climatological spatial comparisons between them less reliable (Westcott, 1995;Changnon, 2001a;Rivas Soriano and de Pablo, 2002;Pinto et al, 2013;Enno, 2014b).…”

Lightning Enhancement in the Amazon Region Due to Urban Activity

“…Since the UHI effect has becoming more prominent along the last decades with the growth of the urban area of Manaus, we have also investigated the time variation of the lightning activity during this period using thunderstorm day data [29]. Thunderstorm day data is the unique information available in Manaus for a long time period.…”