Spatial distribution of the level of return of extreme precipitation events in Northeast Brazil

Abstract

This study aimed to estimate levels of return of extreme daily precipitation events, associating them with natural disasters in Northeast Brazil (NEB), a region characterized by different climatic conditions and low rates of social and economic development. For this, generalized Pareto distribution (GPD) models were adjusted to the daily extreme precipitation data estimated by the Tropical Rainfall Measuring Mission (TRMM) 3B42 product of the multisatellite precipitation analysis for a period of 16 years (2000-2015). In addition, the estimates of the GPD model were compared using two data sources, TRMM and pluviometer. The investigation showed that the results of the GPD model estimated by means of the extreme data from the rain gauge and the TRMM were statistically the same, with 95% confidence. Thus, using the data referring to the 2,082 grid points of the TRMM, it was possible to map the spatial distribution of the estimates of the levels of return of extreme precipitation to the return periods of 2, 5 and 10 years, per seasonal period. In general, the results indicated that the intensity of expected extreme precipitation depends on the seasonal period and the place of occurrence of precipitation. The eastern NEB stood out as the region where the highest intensities of extreme precipitation are expected. Extreme precipitation values of up to 178 mm are expected in 2 years. The areas where natural disasters occurred in the years 2016, 2017 and 2018 are similar to those in which the highest rainfall intensities are expected. The results of this study can allow the evaluation of the spatial distribution of risks related to extreme precipitation events, and therefore, support the planning of regional public policies and environmental management for the prevention of natural disasters in NEB. K E Y W O R D S diaries precipitation, generalized Pareto distribution, natural disaster, TRMM 1 | INTRODUCTION Extreme weather events are one of the main topics studied related to climate change. Future projections released by the Intergovernmental Panel on Climate Change (IPCC) show that these events will become increasingly frequent and intense in several regions of the world, including in areas of Northeast Brazil (NEB; Du et al., 2019). Extreme weather events can cause waves of heat and cold, floods, landslides, droughts and more.

Regionalização e Análise da Tendência da Precipitação do Rio Grande do Norte Associados a Padrões de TSM

“…Existe uma vasta literatura científica acerca da ocorrência de precipitação no Nordeste do Brasil (NEB) (Yamazaki e Rao, 1977;Zhou e Lau, 2001;Carvalho et al, 2002Carvalho et al, , 2004Ferreira e Mello, 2005;Souza e Cavalcanti, 2009;Reboita et al, 2010;Oliveira et al, 2013;Rodrigues et al, 2019;2020), que é caracterizado por apresentar longos períodos de seca Costa et al, 2015;Dos Santos et al, 2019) e ocorrencias de eventos de precipitação intensa (Costa et al, 2015;Oliveira et al, 2017;Da Silva et al, 2019;Rodrigues et al, 2020). O NEB engloba os Estados do Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe e Bahia, totalizando uma área de aproximadamente 1.558.196 km 2 .…”

“…Os VCANs atuam no verão austral com máxima predominância no mês de janeiro (Kousky e Gan, 1981;Coutinho et al, 2010). Os DOL ocorrem durante todo ano (Diedhiou et al, 2010) ao longo da costa NNEB e Leste do NEB (LNEB); contudo são responsáveis por elevados índices pluviométricos nos meses de inverno em regiões do LNEB (Ramos, 1975;Amorim et al, 2019;Rodrigues et al, 2020). Os SF e a ZCAS atuam sobre o setor Sul do NEB (SNEB), em especial, nos meses de novembro a janeiro (Ferreira e Melo, 2005).…”

“…Recentemente, resultados mostraram evidências que eventos extremos de precipitação (EEP) diários apresentou tendência positiva nos últimos anos (Amorim et al, 2019), entre 1986 a 2016, na cidade de Natal. Alguns desses EEP contribuíram para seguidos desastres naturais, em decorrência a existência de áreas de alto risco natural (Moreira et al, 2014;Macedo et al, 2016;Rodrigues et al, 2020) na capital. Além disso, a população da capital também apresenta-se exposta a frequentes alagamentos devido à obras paradas e/ou incompletas do sistema de drenagem da cidade, que são potencializados na ocorrência dos EEP.…”

“…Amorim et al (2019) destacam para a cidade de Natal, em vários anos de El Niños, a variabilidade anual na frequência de EEP diários apresentou-se diferente. Percebe-se que o RN apresenta variabilidadade da precipitação tanto no espaço quanto no tempo (Rodrigues et al, 2020). Sendo assim, estudos que venham a contribuir com informações fundamentais a ações de adaptações às alterações climáticas são de grande valia.…”

Assessing the Tropical South Atlantic atmosphere thermodynamics under distinct Sea Surface Temperature patterns

“…Meanwhile, severe rainfall in coastal areas can lead to flash floods and landslides with deaths and economic losses, mostly due to uneven urban space organization, and the occupation of hills or slopes, which favors geological instability (Gomes et al 2012;Dos Santos et al 2018).The semiarid, which corresponds to an area of about 1,542,000 km2 or ~11% of Brazil, is the region most vulnerable to droughts and desertification in the NEB (Marengo et al 2017;Carvalho et al 2020). In contrast, the Eastern and Northern Northeast Brazilian (ENEB and NNEB) coasts have not only a high susceptibility to intense rainfall episodes, landslides, flash floods, sea-rising damages, but also the most significant number of inhabitants in NEB (Hounsou-gbo et al 2015;Neves et al 2016;Debortoli et al 2017;Rodrigues et al 2020).The rainfall variability in the NEB northern and central semiarid regions is associated with the Inter-Tropical Convergence Zone (ITCZ) north-south migration (Moscati and Gan 2007;Rodrigues et al 2011;Hastenrath 2012;Marengo et al 2017). In the southern, western, and central regions of the NEB, the South Atlantic Convergence Zone (SACZ) variability contributes to the semiarid region's rainfall events during austral spring and summer (Paegle and Mo 2002).…”