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

Abstract

Resumo A precipitação apresenta elevada variabilidade espacial e temporal, a exemplo do Nordeste do (NEB), que é caracterizado por longos períodos de secas e por episódios de chuva excessiva, que interferem no gerenciamento de recursos hídricos. Especificamente o Estado do Rio Grande do Norte (RN), localizado na região oriental do NEB, a estação chuvosa ocorre em dois períodos. Neste contexto, o objetivo principal deste estudo é definir áreas homogêneas de precipitação (AHP) do Estado do RN, investigar tendências lineares e mudanças em que as mesmas ocorreram na estação chuvosa. Utilizaram-se acumulados de precipitação da quarta versão do produto da Universidade de Delaware para o período de 1900 a 2014. Para identificar as AHP utilizou-se a análise de agrupamento. As tendências foram estimadas pelo teste de Mann-Kendall. As quebras de estrutura, pelo método de Pettit. Os resultados indicam três AHP: Oeste, Seridó e Litoral. A estação chuvosa no Oeste e Seridó concentra-se entre fevereiro a maio; no Litoral, entre abril e julho. As tendências são identificadas apenas no Litoral com valor-p < 0,05, um aumento em sua média foi observado a partir de 1964 e isso, aparentemente, está associada aos modos de variabilidade do Atlântico.

Annual Rainfall in Pernambuco, Brazil: Regionalities, Regimes, and Time Trends

“…The main factor that influences rainfall in the state is the ITCZ, which is affected by variations in the sea surface temperature (SST) of the Atlantic Ocean, as pointed out by Menezes et al (2008). The ITCZ is active from summer to autumn, especially in the northern part of the northeast region (Zhou and Lau, 2001;Amorim et al, 2020). Another element are the EWDs, which are small amplitude disturbances with low surface pressure, active in the Northeastern coast, especially from May to August (Yamazaki and Rao, 1977;Chan, 1990;Gomes et al, 2015).…”

“…However, the authors did not investigate annual changes cumulatively. Amorim et al (2020), in turn, divided the state of Rio Grande do Norte into three zones and found that the coastal area displayed statistically significant results and positive trends for annual values.…”

“…Considering these characteristics, the precipitation in the Brazilian Northeast displays great spatiotemporal variability, which makes the identification of homogeneous rainfall zones and their precipitation regimes a valuable approach. Some studies have zoned precipitation through multivariate grouping techniques, such as Macedo et al (2010) in the state of Paraíba; Dourado et al (2013) in the state of Bahia;Oliveira et al (2017) in the whole Northeast; and Amorim et al (2020) in the state of Rio Grande do Norte.…”

Meteorological droughts and water resources: Historical and future perspectives for Rio Grande do Norte state, Northeast Brazil

“…(2017b) and Amorim et al . (2020). The coastal precipitation regime is mainly associated with the Easterly Wave Disturbances (Gomes et al ., 2019), while in the interior of RN is determined mainly by the equatorial positioning of the Intertropical Convergence Zone (ITCZ) (Utida et al ., 2019).…”

“…Several studies have shown that when the equatorial Pacific and tropical North Atlantic are warmer than (colder) average, especially during the austral summer and autumn, drought (wet) years are reported in the RN (e.g., Uvo et al, 1998;Gomes and Lima, 2021). Further information about spatial location of rain gauges and the annual precipitation cycle in RN can be found in Santos e Silva et al (2012), Medeiros et al (2017b) and Amorim et al (2020). The coastal precipitation regime is mainly associated with the Easterly Wave Disturbances (Gomes et al, 2019), while in the interior of RN is determined mainly by the equatorial positioning of the Intertropical Convergence Zone (ITCZ) (Utida et al, 2019).…”