El-Niño southern oscillation and rainfall erosivity in the headwater region of the Grande River Basin, Southeast Brazil

Abstract

Abstract. Relationships between regional climate and oceanic and atmospheric anomalies are important tools in order to promote the development of models for predicting rainfall erosivity, especially in regions with substantial intra-annual variability in the rainfall regime. In this context, this work aimed to analyze the rainfall erosivity in headwaters of Grande River Basin, Southern Minas Gerais State, Brazil. This study considered the two most representative environments, the Mantiqueira Range (MR) and Plateau of Southern Minas Gerais (PSM). These areas are affected by the El Nino Southern Oscillation (ENSO) indicators Sea Surface Temperature (SST) for Niño 3.4 Region and Multivariate ENSO Index (MEI). Rainfall erosivity was calculated for individual rainfall events from January 2006 to December 2010. The analyses were conducted using the monthly data of ENSO indicators and the following rainfall variables: rainfall erosivity (EI30), rainfall depth (P), erosive rainfall depth (E), number of rainfall events (NRE), number of erosive rainfall events (NEE), frequency of occurrence of an early rainfall pattern (EP), occurrence of late rainfall pattern (LP) and occurrence of intermediate rainfall patter (IP). Pearson's coefficient of correlation was used to evaluate the relationships between the rainfall variables and SST and MEI. The coefficients of correlation were significant for SST in the PSM sub-region. Correlations between the rainfall variables and negative oscillations of SST were also significant, especially in the MR sub-region, however, the Person's coefficients were lesser than those obtained for the SST positive oscillations. The correlations between the rainfall variables and MEI were also significant but lesser than the SST correlations. These results demonstrate that SST positive oscillations play a more important role in rainfall erosivity, meaning they were more influenced by El-Niño episodes. Also, these results have shown that the ENSO variables have potential to be useful for rainfall erosivity forecasting in this region.

Calibration and validation of rainfall erosivity estimators for application in Rwanda

“…Wet seasons or years in Rwanda coincide with El Niño and dry seasons are observed during La Niña phenomena (Ngarukiyimana et al, 2018). Previous research in China (Chen and Zha, 2018), US (D'Odorico et al, 2001) and Brazil (Mello et al, 2011) indicated that average rainfall erosivity is stronger during El Niño events and weaker during La Niña events. At monthly temporal resolution, the dataset comprises both dry, normal and wet conditions.…”

The Rise of Climate-Driven Sediment Discharge in the Amazonian River Basin

“…This in turn affects the sediment mobilization associated with erosive rainfall events. In particular, Mello et al [99] found a correlation between erosive events in Brazil and sea surface temperature of the Equatorial Pacific region (El Niño-3.4). This means that in years with significant ENSO events, rainfall regime tends to increase in this region, which implies increased rainfall erosivity and, so, sediment rates.…”

The Investigation of 1997 and 2015 El Nino Events in West Sumatera, Indonesia

“…Ward et al (2016) found by simulation that El Nino events tend to increase not only flood prevalence but also flood duration. In Brazil, El Nino event tends to increase soil erosivity [19]. Since the main stream of the Arau catchment flows through the heart of the City of Padang, its functions as the source of domestic water and for drainage are vital for the city.…”