How the Atlantic multidecadal oscillation (AMO) modifies the ENSO influence on the South American rainfall

Kayano, Mary Toshie; Capistrano, Vinícius

doi:10.1002/joc.3674

Cited by 134 publications

(106 citation statements)

References 64 publications

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“…The linkage between the variability of the Atlantic SST and ENSO through an atmospheric bridge has been suggested by observational studies and coupled GCM (CGCM) experiments (Dong et al 2006;Timmermann et al 2007;Dong and Sutton 2007;Rodríguez-Fonseca et al 2009; López-Parages and Rodríguez-Fonseca 2012; Kayano and Capistrano 2014;Keenlyside et al 2013;Svendsen et al 2013). Using observed data, Rodríguez-Fonseca et al (2009) and Jansen et al (2009) demonstrated the relationship between the tropical Atlantic and Pacific Oceans, with Atlantic SST anomalies leading Pacific SST anomalies by 6 months.…”

Section: Introductionmentioning

confidence: 90%

ENSO Amplitude Modulation Associated with the Mean SST Changes in the Tropical Central Pacific Induced by Atlantic Multidecadal Oscillation

Kang

Kucharski

2014

Journal of Climate

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The mechanism associated with the modulation of the El Niño-Southern Oscillation (ENSO) amplitude caused by the Atlantic multidecadal oscillation (AMO) is investigated by using long-term historical observational data and various types of models. The observational data for the period 1900-2013 show that the ENSO variability weakened during the positive phase of the AMO and strengthened in the negative phase. Such a relationship between the AMO and ENSO amplitude has been reported by a number of previous studies. In the present study the authors demonstrate that the weakening of the ENSO amplitude during the positive phase of the AMO is related to changes of the SST cooling in the eastern and central Pacific accompanied by the easterly wind stress anomalies in the equatorial central Pacific, which were reproduced reasonably well by coupled general circulation model (CGCM) simulations performed with the Atlantic Ocean SST nudged perpetually with the observed SST representing the positive phase of the AMO and the free integration in the other ocean basins. Using a hybrid coupled model, it was determined that the mechanism associated with the weakening of the ENSO amplitude is related to the westward shift and weakening of the ENSO zonal wind stress anomalies accompanied by the westward shift of precipitation anomalies associated with the relatively cold background mean SST over the central Pacific.

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Section: Introductionmentioning

confidence: 90%

ENSO Amplitude Modulation Associated with the Mean SST Changes in the Tropical Central Pacific Induced by Atlantic Multidecadal Oscillation

Kang

Kucharski

2014

Journal of Climate

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“…Rao et al (1995) suggest that the drought of 1993 is connected, at least partially, to unusual El Niño-Southern Oscillation (ENSO) conditions that occurred during that year. It is well known that climate in northeast Brazil is strongly dependent on sea surface temperature (SST) in the Pacific and Atlantic (Kayano and Capistrano, 2013), with several previous studies indicating that droughts in that region are effectively associated with El Niño events and a warmer (cooler) than normal North (South) tropical Atlantic Ocean SST (Chiang et al, 2002;Magrin et al, 2007). Similarly, the 2012-2013 drought appears to have been caused by anomalous lower patterns of SST concentrated in the central Pacific that may have been sufficient to significantly alter precipitation regimes in the region along 2012 and 2013 (Marengo et al, 2013;Rodrigues and McPhaden, 2014;Pereira et al, 2014).…”

Section: Spatio-temporal Characterization Of Drought With the Essmimentioning

confidence: 97%

An empirical standardized soil moisture index for agricultural drought assessment from remotely sensed data

Carrão

Russo

Sepulcre-Cantó

et al. 2016

International Journal of Applied Earth Observation and Geoinfor

140

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a b s t r a c tWe propose a simple, spatially invariant and probabilistic year-round Empirical Standardized Soil Moisture Index (ESSMI) that is designed to classify soil moisture anomalies from harmonized multi-satellite surface data into categories of agricultural drought intensity. The ESSMI is computed by fitting a nonparametric empirical probability density function (ePDF) to historical time-series of soil moisture observations and then transforming it into a normal distribution with a mean of zero and standard deviation of one. Negative standard normal values indicate dry soil conditions, whereas positive values indicate wet soil conditions. Drought intensity is defined as the number of negative standard deviations between the observed soil moisture value and the respective normal climatological conditions. To evaluate the performance of the ESSMI, we fitted the ePDF to the Essential Climate Variable Soil Moisture (ECV SM) v02.0 data values collected in the period between January 1981 and December 2010 at South-Central America, and compared the root-mean-square-errors (RMSE) of residuals with those of beta and normal probability density functions (bPDF and nPDF, respectively). Goodness-of-fit results attained with time-series of ECV SM values averaged at monthly, seasonal, half-yearly and yearly timescales suggest that the ePDF provides triggers of agricultural drought onset and intensity that are more accurate and precise than the bPDF and nPDF. Furthermore, by accurately mapping the occurrence of major drought events over the last three decades, the ESSMI proved to be spatio-temporal consistent and the ECV SM data to provide a well calibrated and homogenized soil moisture climatology for the region. Maize, soybean and wheat crop yields in the region are highly correlated (r > 0.82) with cumulative ESSMI values computed during the months of critical crop growing, indicating that the nonparametric index of soil moisture anomalies can be used for agricultural drought assessment.

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“…It is known that the AMV has an impact on weather and climate predominantly in the Northern Hemisphere, for example, North American and European climate (Sutton and Hodson 2005;Nigam et al 2011), Arctic temperature change (Chylek et al 2009), and temperature over the whole Northern Hemisphere (Steinman et al 2015). A warm phase of the AMV is associated with droughts (McCabe et al 2004) and decreased rainfall in the United States (Enfield et al 2001) but more rainfall in the Sahel region (Folland et al 1986) and India (Zhang and Delworth 2006), as well as stronger Atlantic hurricane activity (Goldenberg et al 2001;Nigam and Guan 2011) and stronger El Niño or weaker La Niña events including respective changes in South American rainfall (Kayano and Capistrano 2014).…”

Section: Introductionmentioning

confidence: 99%

Evolution of the Atlantic Multidecadal Variability in a Model with an Improved North Atlantic Current

Drews

Greatbatch

2017

J. Climate

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This article investigates the dynamics and temporal evolution of the Atlantic multidecadal variability (AMV) in a coupled climate model. The model contains a correction to the North Atlantic flow field to improve the path of the North Atlantic Current, thereby alleviating the surface cold bias, a common problem with climate models, and offering a unique opportunity to study the AMV in a model. Changes in greenhouse gas forcing or aerosol loading are not considered. A striking feature of the results is the contrast between the western and eastern sides of the subpolar gyre in the model. On the western side, anomalous heat supply by the ocean plays a major role, with most of this heat being given up to the atmosphere in the warm phase, largely symmetrically about the time of the AMV maximum. By contrast, on the eastern side, the ocean anomalously gains heat from the atmosphere, with relatively little role for ocean heat supply in the years before the AMV maximum. Thereafter, the balance changes with heat now being anomalously removed from the eastern side by the ocean, leading to a reduced ocean heat content, behavior associated with the establishment of an intergyre gyre at the time of the AMV maximum. In the warm phase, melting sea ice leads to a freshening of surface waters northeast of Greenland that travel southward into the Irminger and Labrador Seas, shutting down convection and terminating the AMV warm phase.

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How the Atlantic multidecadal oscillation (AMO) modifies the ENSO influence on the South American rainfall

Cited by 134 publications

References 64 publications

ENSO Amplitude Modulation Associated with the Mean SST Changes in the Tropical Central Pacific Induced by Atlantic Multidecadal Oscillation

ENSO Amplitude Modulation Associated with the Mean SST Changes in the Tropical Central Pacific Induced by Atlantic Multidecadal Oscillation

An empirical standardized soil moisture index for agricultural drought assessment from remotely sensed data

Evolution of the Atlantic Multidecadal Variability in a Model with an Improved North Atlantic Current

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