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The occurrence of natural disasters and extreme events caused by precipitation has been directly affecting the population of the state of Rio de Janeiro. However, studies that seek to understand and identify changes in the variability of this meteorological element are scarce for the southern region of the state of Rio de Janeiro. In this context,...
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... Extreme rainfall events stand out among the most disturbing atmospheric phenomena, since they can have negative and significant socioeconomic and environmental impact on different populations (Liebmann et al. 2001). Scientific studies available in the literature highlight the application of climate change indices (Zhang et al. 2011) to identify changes in rainfall rates and extreme events; among them, one finds Halimatou et al. (2017), Shi et al. (2017), Shao et al. (2019), Terassi et al. (2022) and Carvalho and Wanderley (2022). Thus, coherent assessments of changes in rainfall rates should analyze extreme events of consecutive dry and wet days, daily rainfall rate higher than the 95th percentile and total rainfall rates (Casanueva et al. 2014). ...
... Southern winds carry moisture from the ocean toward the continent and increase convergence on the coast; this phenomenon generates upward movement of water vapor and enables moisture to rise into the lower atmosphere. Carvalho and Wanderley (2022) showed that for the last decades, the total annual precipitation and consecutive wet days have decreased, which is mainly due to increase on consecutive dry days. ...
... Madureira, Santa Cruz and Grota Funda have shown trend increase in SDII; however, SDII has decreased after 2005 in almost all neighborhoods, as previously observed for PRCPTOT and CWD; this outcome has indicated reduced annual rainfall rate and number of wet days. Similar results were found by Carvalho and Wanderley (2022) which SDII also showed reduction trend and the decrease in annual precipitation is causing the SDII to decrease, as the number of consecutive wet days is also decreasing. The reduction in rainfall in the CRJ exacerbates the problem experienced in recent years of urban supply, which was aggravated by the 2014 water crisis in Southeast Brazil. ...
Increased temperature rates have the potential to change the rainfall regime in a given region, as well as to intensify its extreme events, which may lead to significant and negative socioeconomic and environmental impacts on urban populations. However, knowledge about the extent of changes in rainfall rates in Rio de Janeiro City (RJC) remains incipient; thus, it is necessary applying indices climate change to help better understanding this phenomenon. The aim of the current study is to investigate changes in rainfall distribution and increase in the number of extreme rainfall events in RJC. Daily rainfall data deriving from fifteen weather stations distributed in RJC were analyzed in the RclimDex software and Mann–Kendall test. The analysis has shown increased rainfall rates from the beginning of the series to approximately the first ten years of study. Total rainfall rate has decreased after this period. Rainfall intensity in almost all seasons has decreased after 2005; this outcome has indicated reduced annual rainfall rate and number of wet days. However, there was prevalence of positive trends in daily rainfall rates (Rx1day) and in total rainfall of five consecutive days (Rx5day). The increased number of extreme rainfall events in RJC can cause sudden inundations, floods, runoffs and river overflows with potential to cause landslides and human death due to irregular occupation of hills and slopes.
Desertification is considered to be among the most serious environmental problems; it has social, economic, and environmental effects. Identifying areas susceptible to desertification (ASD) can support planning for rational water use because these areas have limited water and are affected by climate variability. This work aimed to identify current and potential ASDs in Brazil to construct future climate change scenarios (FCCSs). Air temperature and precipitation data for Brazil for the baseline period 1990 to 2018 were used to project FCCSs from 2021 to 2100. For the FCCSs, the Coupled Model Intercomparison Project (specifically, CMIP6) projections for the Shared Socioeconomic Pathways (SSP) 4.5 scenario were used. SSP 8.5 was used to calculate the Aridity Index (AI). The results indicated a temperature increase of 3 to 6 °C in Brazil, with a variation in precipitation of approximately − 10.0 to 6.0% by 2100. The projections indicate an increase in areas of dry subhumid climate in Brazil, with a trend of high and moderate susceptibility to desertification, in addition to a significant increase in semi-arid areas, with a trend of high susceptibility to desertification by 2100. Climate change is likely to increase areas with high susceptibility to desertification in Brazil.
