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

Alan Cezar Bezerra,Geber Barbosa De Albuquerque Moura,Cristina Rodrigues Nascimento,Jhon Lennon Bezerra Da Silva,Pabrício Marcos Oliveira Lopes,Athos Murilo Queiroz Araújo,Sidney Anderson Teixeira Da Costa

doi:10.1590/0102-77863630129

Alan Cezar Bezerra, Geber Barbosa De Albuquerque Moura + Show 5 more

Open Access

https://doi.org/10.1590/0102-77863630129

Copy DOI

Abstract

Abstract This study aimed to identify the homogeneous zones, the regimes, and the local trends for annual and seasonal rainfall in the state of Pernambuco, Brazil. We collected seasonal and annual data on monthly rainfall from 45 weather stations in Pernambuco from 1987 to 2019. The data were organized yearly to identify the homogeneous rainfall zones based on Euclidean distance and Ward's coefficient. The mean annual value of each zone was calculated and the data were subjected to descriptive statistics analysis, analysis of rainfall regime with the Rain Anomaly Index, and time trend analysis using the Mann-Kendall method. The results show three homogeneous rainfall zones: 1 (semiarid), 2 (transition), and 3 (coastal), with mean values for annual rainfall of 562, 1032, and 1812 mm year-1, respectively. The precipitation regime showed the predominance of dry years as zones 1, 2, and 3 exhibited dry periods of 18, 17, and 15 years, respectively. Time trend analysis revealed a decrease in annual rainfall of 48.7 mm for Zone 1, 13.2 mm for Zone 2, and 204.4 mm for Zone 3, without statistical significance. Seasonal analysis demonstrated that Zone 1 presented a negative trend in the spring and a positive trend in Zone 2 in the summer, indicating changes in the rain seasonality.

Highlights

Climate variability is a natural process triggered by a combination of temporal and spatial scales of meteorological systems (Silva et al, 2018)
Analysis of statistical values for the zones (Fig. 3) and the maps (Figs. 2A-B) revealed the differences between the zones: Zone 1 is mostly located in the semiarid region according to Koppen's classification (Alvares et al, 2013); Zone 2 has higher rainfall values than Zone 1, forming a transition area between zones 1 and 3; and Zone 3 is located in the coastal area and presents higher rainfall values
Considering the above, this study identified the annual homogenous rainfall zones, rainfall regime, dry and wet seasons, and time trends for rainfall in Pernambuco

Summary

Introduction

Climate variability is a natural process triggered by a combination of temporal and spatial scales of meteorological systems (Silva et al, 2018). Evidence suggests that climate changes due to different factors, both anthropogenic and natural, causing global, regional, and local effects (Guimarães et al, 2016). According to the most recent report by the Intergovernmental Panel on Climate Change (IPCC, 2018), global temperature is likely to increase 1.5 °C with heavy precipitation and the probability of drought and precipitation deficits between 2030 and 2052. Among the meteorological elements affected by climate change, precipitation has a significant influence on human activity. In Northeast Brazil, analyses results suggest climate changes with an increase in the amplitude of seasonality that intensify drought in the dry season and humidity in the rainy season (Oliveira et al, 2014; Oliveira et al, 2017; Silva et al, 2019). Rainfall predictions can reduce the negative impact on human activity as well as guide plans and decisions for the adequate employment of water resources (Terassi et al, 2018) to mitigate possible conflicts

Objectives

Methods

Results

Conclusion