Rainfall pattern and erosion potential in the physiographic regions of the state of Pernambuco, Brazil

Antonio G Pinheiro,Suzana M G L Montenegro,Abelardo A De A Montenegro,Sérgio M S Guerra,Thais E M Dos S Souza

doi:10.1590/1807-1929/agriambi.v22n12p849-853

Abstract

ABSTRACT The objective of the present study was to characterize the spatial and temporal (2000-2015) rainfall pattern variability and erosive potential in the different physiographic regions of the state of Pernambuco, Brazil. Rainfall data series (3 to 12 years) from 25 weather stations of the state were analyzed. Erosive rainfall events (more than 10 mm depth) were considered to evaluate the annual erosivity index, monthly erosivity index (EI30), rainfall erosivity factor (R), and rainfall pattern. The inverse distance weighting (IDW) - inverse of the square of the distance - was used to create spatial interpolation and develop maps. The rainfall data from the weather stations showed average annual rainfall of 827 mm and average erosivity of 4,784 MJ mm ha-1 h-1. The Metropolitan region of Pernambuco presented the highest rainfall erosivity index, with annual average of 9,704 MJ mm ha-1 h-1; and the Sertão do São Francisco region had the lowest, with annual average of 4,902 MJ mm ha-1 h-1. The state of Pernambuco presented advanced (42%), intermediate (38%), and delayed (20%) rainfall patterns.

Highlights

IntroductionRainfall is the main factor that affects soil erosion, it can damage agricultural lands due to nutrient losses, and cause serious problems for agricultural activities, and water pollution (Eltz et al, 2013; Moreno et al, 2014).Estimating the rainfall erosivity factor (R) of the universal soil loss equation (USLE) requires the calculation of the rainfall erosivity index (EI30), which is the product from two specific parameters of erosive precipitations in a location: total kinetic energy of the rainfall (E), and maximum intensity of rainfall in 30 min (I30).Several studies have estimated erosivity index in 30 min (EI30) for different regions and environments (Oliveira et al, 2012; Santos & Montenegro, 2012; Amaral et al, 2014; Moreno et al, 2014; Isikwue et al, 2015; Panagos et al, 2016). Oliveira et al (2012) reviewed the rainfall erosivity in Brazil and reported values of 1,672 to 22,452 MJ mm ha-1 h-1.The physiographic regions of the state of Pernambuco present high rainfall variability, with climate varying from humid (‘Zona da Mata’, and Coastal) to hot semiarid (‘Sertão’) (Cantalice et al, 2009).Little spatial and temporal information for the calculation of erosivity index is found in Brazil, hindering studies on these parameters in several regions of the country, since they require high-resolution long-period continuous rainfall data (Trindade et al, 2016)
Estimating the rainfall erosivity factor (R) of the universal soil loss equation (USLE) requires the calculation of the rainfall erosivity index (EI30), which is the product from two specific parameters of erosive precipitations in a location: total kinetic energy of the rainfall (E), and maximum intensity of rainfall in 30 min (I30)
The objective of the present study was to improve the information on rainfall spatial distribution, rainfall erosivity index (EI30), and rainfall pattern of the state of Pernambuco, Brazil, by characterizing the rainfall spatial variability and erosion potential, and estimate the rainfall patterns of the different regions of this state

Summary

Introduction

Rainfall is the main factor that affects soil erosion, it can damage agricultural lands due to nutrient losses, and cause serious problems for agricultural activities, and water pollution (Eltz et al, 2013; Moreno et al, 2014).Estimating the rainfall erosivity factor (R) of the universal soil loss equation (USLE) requires the calculation of the rainfall erosivity index (EI30), which is the product from two specific parameters of erosive precipitations in a location: total kinetic energy of the rainfall (E), and maximum intensity of rainfall in 30 min (I30).Several studies have estimated EI30 for different regions and environments (Oliveira et al, 2012; Santos & Montenegro, 2012; Amaral et al, 2014; Moreno et al, 2014; Isikwue et al, 2015; Panagos et al, 2016). Oliveira et al (2012) reviewed the rainfall erosivity in Brazil and reported values of 1,672 to 22,452 MJ mm ha-1 h-1.The physiographic regions of the state of Pernambuco present high rainfall variability, with climate varying from humid (‘Zona da Mata’, and Coastal) to hot semiarid (‘Sertão’) (Cantalice et al, 2009).Little spatial and temporal information for the calculation of erosivity index is found in Brazil, hindering studies on these parameters in several regions of the country, since they require high-resolution long-period continuous rainfall data (Trindade et al, 2016). Rainfall is the main factor that affects soil erosion, it can damage agricultural lands due to nutrient losses, and cause serious problems for agricultural activities, and water pollution (Eltz et al, 2013; Moreno et al, 2014). Estimating the rainfall erosivity factor (R) of the universal soil loss equation (USLE) requires the calculation of the rainfall erosivity index (EI30), which is the product from two specific parameters of erosive precipitations in a location: total kinetic energy of the rainfall (E), and maximum intensity of rainfall in 30 min (I30). Little spatial and temporal information for the calculation of erosivity index is found in Brazil, hindering studies on these parameters in several regions of the country, since they require high-resolution long-period continuous rainfall data (Trindade et al, 2016)

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