Resumo Este trabalho tem como objetivo contribuir com o estudo da precipitação na cidade de Salvador–BA. Os totais mensais de precipitação obtidos pelo Instituto Nacional de Meteorologia no período de 51 anos (1961-2011) fundamentaram esta pesquisa. A variabilidade pluviométrica foi analisada com ênfase na determinação das classes da precipitação nas escalas anual, quadrimestral e mensal. Foram utilizados os testes de significância não paramétricos de Mann-Kendall e as estimativas de inclinação pelo método da Curvatura de Sen. Na classificação pluviométrica foi utilizado o Método dos Percentis (Quantis). Para a análise anual, os resultados mostraram que 1964 (1961) foi um ano classificado como “muito chuvoso” (“muito seco”). Na análise do quadrimestre mais chuvoso AMJJ (mais seco ASON), o ano de 1971 (1980) foi o mais extremo “muito chuvoso” (“muito seco”). Na análise mensal, o evento que obteve maior volume pluviométrico ocorreu em abril de 1984 com registros de 889,8 mm. A análise da tendência mostrou uma redução no volume de chuva na escala anual, entretanto, sem significância estatística. Grande parte dos eventos analisados ocorreram com condições oceânicas no Pacífico equatorial e/ou Atlântico Sul Tropical favoráveis (desfavoráveis) ao aumento (diminuição) do volume de chuva na área em estudo, tendo por base uma análise qualitativa.

Knowledge about regions where lightning occurs is important both for understanding storm development and direction. This can assist in very short-term weather forecasts and in developing lightning warning systems, aiming to minimize exposure of people and equipment in the open sky. A survey on the occurrence of lightning in different types of land use and coverage and different elevation strata in the region of the Itacaiúnas River watershed (IRW), located in the Carajás Mineral Province, in the Eastern Amazon, from 2012 to 2021 was conducted. The results showed significant differences in the occurrence of lightning in mining areas and deforested areas. When comparing the large proportion of deforested areas with the mining area, the results suggested that in IRW mining areas, the lightning incidence is expressively higher. The assessment of electrical activity at different elevations in the region suggested that the slope of the terrain and its thermodynamic effects on the formation of storms have more influence than altitude on lightning activity. The results showed the importance of adopting initiatives aimed at protecting both the local population and mining workers, as well as equipment exposed to the open sky in this region.

Operational records of power outages of the electric energy distribution systems in eastern Amazonia presented a large number of events attributed to lightning strikes, during the 2006 to 2009 period. The regional electricity concessionary data were compared to actual lightning observations made by SIPAM's LDN system, over two areas where operational sub systems of transmission lines are installed. Statistical relations were drawn between the monthly lightning occurrence density and the number of power outages of the electric systems for both areas studied. The results showed that, although with some delays between these variables peaks, the number of power disruptions has a tendency to follow the behavior of the lightning occurrence densities variations. The numerical correlations were positive and may be useful to the transmission lines maintenance crews at least for the Belém-Castanhal electricity distribution sub system. Evidence was found, that the SST's over certain areas of the Pacific and Atlantic Oceans, influence convection over the area of interest, and may help to prognosticate the periods of intense electric storms, requiring repair readiness for the regional electric systems.