Joint Diagnostic of the Surface Air Temperature in Southern South America and the Madden–Julian Oscillation

Naumann, Gustavo; Vargas, Walter M.

doi:10.1175/2010waf2222418.1

Cited by 21 publications

(13 citation statements)

References 19 publications

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“…In this sense, the present results provide an alternative perspective on the predictability of the intraseasonal component of summer SAT in Patagonia. This conclusion stands out, in agreement with the recent results of Alvarez et al [2015], and in spite of previous related findings, which showed that the mutual information between SAT and the MJO is highest not in Patagonia but in southeastern Brazil and northeastern Argentina, and features its maximum in autumn and winter and its minimum in summer [Naumann and Vargas, 2010]. Concerning the regional-and large-scale circulation patterns associated with the MJO signal in Eastern Patagonia, we found that positive (negative) SAT anomalies are linked to a midlevel anticyclonic (cyclonic) circulation anomaly centered over the southwest Atlantic and extending over southern South America, in agreement with previous work on regional summer SAT means [Jacques-Coper and Brönnimann, 2014].…”

Section: Discussionsupporting

confidence: 92%

“…This conclusion stands out, in agreement with the recent results of Alvarez et al . [], and in spite of previous related findings, which showed that the mutual information between SAT and the MJO is highest not in Patagonia but in southeastern Brazil and northeastern Argentina, and features its maximum in autumn and winter and its minimum in summer [ Naumann and Vargas , ].…”

Section: Discussionsupporting

confidence: 66%

“…The intraseasonal variability range has been reported to exhibit a notorious impact in temperature (especially in minimum temperature) in southeastern South America during winter [Naumann and Vargas, 2012]. For this region and season, Naumann and Vargas [2010] showed consistent covariability of temperature and precipitation with the MJO. The MJO is the dominant mode of intraseasonal variability of the tropical coupled ocean-atmosphere system.…”

Section: Introductionmentioning

confidence: 89%

“…The modulation of regional weather and climate systems by the MJO, especially in subtropical latitudes, has been extensively studied, regarding both precipitation [e.g., Sperber , ; Donald et al ., ; Kanamori et al ., ; Matthews et al ., ] and temperature [e.g., Maloney and Kiehl , ; Oliver , ; Salby and Hendon , ; Zhou et al ., ]. Large‐scale impacts associated with this mode have also been described for climates of higher latitudes, both in the Northern Hemisphere [ Vecchi and Bond , ; Cassou , ] and in the Southern Hemisphere, in particular, South America [e.g., Moore et al ., ; Naumann and Vargas , ; Barrett et al ., ; Juliá et al ., ].…”

Section: Introductionmentioning

confidence: 99%

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Evidence for a modulation of the intraseasonal summer temperature in Eastern Patagonia by the Madden‐Julian Oscillation

et al. 2015

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We describe the relationship between the intraseasonal component of surface air temperature (SAT) variability in Eastern Patagonia and the Madden-Julian Oscillation (MJO) during austral summer based on~50 years of daily instrumental records, the Twentieth Century Reanalysis, and a century-long MJO index reconstruction. Our results show that the summer SAT variability in Patagonia is highly driven by the intraseasonal activity (~80%), especially by that associated with the MJO. The active MJO phases modulate the spatial mean intraseasonal temperature signal in Eastern Patagonia with~1.5°C of amplitude. In most of the region, the warmest (coldest) conditions are found during active phase 8 (4). These opposite states of the temperature perturbations are related to almost inverse midlevel circulation anomalies over southern South America and the southwest Atlantic, which are part of a large-scale Rossby-like wave train of alternating circulation anomalies extended along the South Pacific. The corresponding outgoing longwave radiation anomalies suggest that these structures may be triggered by anomalous convection in the tropics. Furthermore, we show that intraseasonal heat waves in southeastern Patagonia tend to occur during active MJO phase 8. These events are also induced by a wave train pattern over the South Pacific, associated with other intraseasonal variability sources. Hence, as shown in a case study, circulation anomalies over the South Pacific triggered, in general, by tropical convection variability and, in particular, by the MJO activity may constructively interact with circulation patterns resulting from the extratropical dynamics, eventually leading to intraseasonal heat waves in southeastern Patagonia.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 66%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evidence for a modulation of the intraseasonal summer temperature in Eastern Patagonia by the Madden‐Julian Oscillation

et al. 2015

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“…Also, several MI metrics were developed to assist in predictor selection for hydroclimatic forecasting [ 48 , 49 ]. More importantly, MI was able to detect the presence of strong nonlinear associations of streamflow, rainfall, and global mean temperature with several large-scale climatic variables [ 31 , 50 , 51 , 52 , 53 , 54 ].…”

Section: Introductionmentioning

confidence: 99%

Information Entropy Suggests Stronger Nonlinear Associations between Hydro-Meteorological Variables and ENSO

Mishra

Konapala

2018

Entropy

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Abstract:Understanding the teleconnections between hydro-meteorological data and the El Niño-Southern Oscillation cycle (ENSO) is an important step towards developing flood early warning systems. In this study, the concept of mutual information (MI) was applied using marginal and joint information entropy to quantify the linear and non-linear relationship between annual streamflow, extreme precipitation indices over Mekong river basin, and ENSO. We primarily used Pearson correlation as a linear association metric for comparison with mutual information. The analysis was performed at four hydro-meteorological stations located on the mainstream Mekong river basin. It was observed that the nonlinear correlation information is comparatively higher between the large-scale climate index and local hydro-meteorology data in comparison to the traditional linear correlation information. The spatial analysis was carried out using all the grid points in the river basin, which suggests a spatial dependence structure between precipitation extremes and ENSO. Overall, this study suggests that mutual information approach can further detect more meaningful connections between large-scale climate indices and hydro-meteorological variables at different spatio-temporal scales. Application of nonlinear mutual information metric can be an efficient tool to better understand hydro-climatic variables dynamics resulting in improved climate-informed adaptation strategies.

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The Influence of Recurrent Modes of Climate Variability on the Occurrence of Monthly Temperature Extremes Over South America

et al. 2017

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The associations between extreme temperature months and four prominent modes of recurrent climate variability are examined over South America. Associations are computed as the percent of extreme temperature months concurrent with the upper and lower quartiles of the El Niño–Southern Oscillation (ENSO), the Atlantic Niño, the Pacific Decadal Oscillation (PDO), and the Southern Annular Mode (SAM) index distributions, stratified by season. The relationship is strongest for ENSO, with nearly every extreme temperature month concurrent with the upper or lower quartiles of its distribution in portions of northwestern South America during some seasons. The likelihood of extreme warm temperatures is enhanced over parts of northern South America when the Atlantic Niño index is in the upper quartile, while cold extremes are often association with the lowest quartile. Concurrent precipitation anomalies may contribute to these relations. The PDO shows weak associations during December, January, and February, while in June, July, and August its relationship with extreme warm temperatures closely matches that of ENSO. This may be due to the positive relationship between the PDO and ENSO, rather than the PDO acting as an independent physical mechanism. Over Patagonia, the SAM is highly influential during spring and fall, with warm and cold extremes being associated with positive and negative phases of the SAM, respectively. Composites of sea level pressure anomalies for extreme temperature months over Patagonia suggest an important role of local synoptic scale weather variability in addition to a favorable SAM for the occurrence of these extremes.

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Joint Diagnostic of the Surface Air Temperature in Southern South America and the Madden–Julian Oscillation

Cited by 21 publications

References 19 publications

Evidence for a modulation of the intraseasonal summer temperature in Eastern Patagonia by the Madden‐Julian Oscillation

Evidence for a modulation of the intraseasonal summer temperature in Eastern Patagonia by the Madden‐Julian Oscillation

Information Entropy Suggests Stronger Nonlinear Associations between Hydro-Meteorological Variables and ENSO

The Influence of Recurrent Modes of Climate Variability on the Occurrence of Monthly Temperature Extremes Over South America

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