Precipitation response to El Niño/La Niña events in Southern South  America – emphasis in regional drought occurrences

Penalba, Olga Clorinda; Rivera, Juan Antonio

doi:10.5194/adgeo-42-1-2016

Cited by 78 publications

(45 citation statements)

References 54 publications

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“…Three drought categories were used for hydrological drought assessment, based on the categories established for the SPI to define meteorological drought conditions [36]. Table 2 shows the SSI categories, which are in line with recent research based on the SSI [31,32,37,38] and will help to compare the results obtained considering meteorological drought assessment based on the SPI over SSA (e.g., [39]). …”

Section: Methodsmentioning

confidence: 55%

Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina

Rivera

Penalba

Villalba

et al. 2017

Water

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During the period 2010-2015, the semi-arid Central Andes in Argentina (CAA) experienced one of the most severe and long-lasting hydrological droughts on record. Since the snowmelt is the most important source of water, the reduced snowfall over the mountains propagated the drought signal through the streamflows in the adjacent foothills east of the Andes ranges. Motivated by the widespread impacts on the socio-economic activities in the region, this study aims to characterize the recent hydrological drought in terms of streamflow deficits. Based on streamflow data from 20 basins, we used the standardized streamflow index (SSI) to characterize hydrological droughts during the period 1971-2016. We found that the regional extent of the 2010-2015 hydrological drought was limited to the basins located north of 38 • S, with mean duration of 67 months and maximum drought severity exhibiting a heterogeneous pattern in terms of spatial distribution and time of occurrence. The drought event reached extreme conditions in 14 of the 15 basins in the CAA, being record-breaking drought in six of the basins. This condition was likely driven by a cooling in the tropical Pacific Ocean resembling La Niña conditions, which generated a decrease in snowfall over the Andes due to suppressed frontal activity.

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Section: Methodsmentioning

confidence: 55%

Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina

Rivera

Penalba

Villalba

et al. 2017

Water

View full text Add to dashboard Cite

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“…In the southern region of Brazil, El Niño events cause increased precipitation and higher temperatures. In contrast, intense La Niña events can produce severe droughts (Grimm and Tedeschi, 2009; Abelen et al, 2015; Penalba and Rivera, 2016).…”

Section: Discussionmentioning

confidence: 99%

Genetic Gain Over 30 Years of Spring Wheat Breeding in Brazil

et al. 2019

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Wheat (Triticum aestivum L.) is one of the most important crops in the world. Brazil is one of the largest importers of this cereal, and wheat breeding programs are attempting to increase productivity and reduce external dependence. The objectives of this study were to quantify the spring wheat genetic gain in Brazil between 1984 and 2014 using data from multienvironment trials, and to verify if the genetic gain stagnated after the 2000s. This study used a highly unbalanced dataset containing grain yield (GY) data from 187 spring wheat trials that were performed at 25 locations between 2002 and 2015. In total, 126 cultivars, released between 1985 and 2014, were evaluated over 14 crop seasons. The cultivar evaluation indicated that there was a genetic gain in GY of 33.9 kg ha−1 yr−1 (r2 = 0.53, P < 0.01), which represents an increase of 1.28% yr−1. The dataset showed a linear regression for the genetic gain and indicates that wheat genetic gain has not stagnated in Brazil after the 2000s.

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“…de Oliveira‐Júnior et al () studied the relationship of SPI and ENSO/PDO for 14 rainfall stations in Brazil and detected indirect relationships of oscillations on the occurrence of drought events by using different correlations. Penalba and Rivera () studied the ENSO influences on SPI (3 and 12 months) for Southern South America by using principal component analysis in seven climatically and geographically homogenous regions. In their study they identified for all regions signals of El Niño (wet conditions) and La Niña (dry conditions) in the SPI indices, being more consistent during El Niño events.…”

Section: Introductionmentioning

confidence: 99%

Observed trends and relationships between ENSO and standardized hydrometeorological drought indices in central Chile

Oertel

Meza

Gironás

2019

Hydrological Processes

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Droughts are natural phenomena that severely affect socio economic and ecological systems. In Chile, population and economic activities are highly concentrated in its central region (i.e. between latitudes 29 S and 40 S), which periodically suffers from severe droughts affecting agriculture, hydropower, and mining. Understanding the dynamics of droughts and large-scale atmospheric processes that influence the occurrence of dry spells is essential for forecasting and efficient early detection of drought events. Central Chile's climate is marked by a significant El Niño Southern Oscillation (ENSO) influence that might help to better characterize droughts as well as to identify the effects of ENSO on the spatial and temporal characteristics of meteorological and hydrological droughts in the region. We analysed the behaviour of the Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Streamflow Index (SSI) time series for 6-month accumulation periods over the austral winter and summer seasons. Multiple linear regression (MLR) and Generalized Linear Models (GLM) showed a significant ENSO influence on dry events for SPEI-6 and SSI-6 during winter and summer. We found that the magnitude of correlation between ENSO and SPEI-6 has changed over the last decades becoming weaker in winter periods and increasing in spring summer periods. Increasing trends in meteorological and hydrological drought events were also identified, along all latitudes, with significant trends during winter in the southern latitudes, and during summer in the semi-arid and Mediterranean zones. These results indicate that drought mitigation actions and policies are necessary to overcome their adverse effects. Given the monthly persistence of ENSO and its relationship to drought indices, there are opportunities for drought monitoring and seasonal forecasting that could become part of national drought management systems.

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Precipitation response to El Niño/La Niña events in Southern South America – emphasis in regional drought occurrences

Cited by 78 publications

References 54 publications

Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina

Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina

Genetic Gain Over 30 Years of Spring Wheat Breeding in Brazil

Observed trends and relationships between ENSO and standardized hydrometeorological drought indices in central Chile

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