Asymmetry of the winter extra-tropical teleconnections in the Northern Hemisphere associated with two types of ENSO

Feng, Juan; Chen, Wen; Li, Yanjie

doi:10.1007/s00382-016-3196-2

Cited by 83 publications

(54 citation statements)

References 60 publications

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“…For the WET‐LN events, the negative SST anomalies to the east of 140°W propagate westwards during the onset and developing LN stages, reach the equatorial central Pacific in OND(0), when they start to strengthen with the largest values expanding into the central equatorial Pacific in the mature LN stage (Figure a). Thereby, these features are consistent with an EP LN event (Zhang et al ., ; Feng et al ., ). Meanwhile, for the DRY events, the largest negative SST anomalies remain in the equatorial central Pacific west of 120°W in all stages (Figure b).…”

Section: Resultssupporting

confidence: 80%

Effects of two different La Niña types on the South American rainfall

Andreoli

Kayano

Viegas

et al. 2018

Intl Journal of Climatology

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The paper tests if the two La Niña (LN) types can be distinguished from each other using their climate impacts on northeastern Brazil (NEB). To this end, all LN events during the 1901–2010 period followed by a wet or dry rainy season (from February to April) in NEB are classified into two categories: WET‐LN and DRY‐LN. The global and regional anomalous atmospheric circulation patterns and the rainfall anomaly patterns in South America associated with the two cases are analysed. The WET‐LN and DRY‐LN events present, respectively, the eastern Pacific LN and central Pacific LN sea surface temperature (SST) anomaly features in the tropical Pacific. On the other hand, the WET‐LN features an interhemispheric SST dipole pattern in the tropical Atlantic, and the DRY‐LN, colder‐than‐normal surface waters in the tropical South Atlantic (TSA) and equatorial Atlantic during MAM(+1). The two analysed cases show regional differential circulation patterns in all seasons. The anomalous wetness over northern and northwestern South America occurs for the WET‐LN type during JJA(0)–DJF(+1) and for the DRY‐LN type, during DJF(+1)–MAM(+1). The anomalous dryness over SESA is more evident for the WET‐LN during JJA(0) and MAM(+1), and for the DRY‐LN, during SON(0). Anomalous dryness occurs in central and eastern South America noted during JJA(0) and DJF(+1) for both cases analysed. The precipitation anomalies in northern South America during DJF(+1) are stronger and more extensive for the DRY‐LN than for the WET‐LN events due to the action of both the anomalous (double) Walker and Hadley cells for the DRY‐LN, in contrast with the exclusive action of an anomalous Walker cell for the WET‐LN case. Also, a double Walker cell drives the dry–wet dipole between northern South America and NEB during MAM(+1) for the DRY‐LN. Our results might be useful mainly for climate monitoring purposes.

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Section: Resultssupporting

confidence: 80%

Effects of two different La Niña types on the South American rainfall

Andreoli

Kayano

Viegas

et al. 2018

Intl Journal of Climatology

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“…This pattern is exemplified by the lack of eastern heating and increased west central tropical Pacific heating during 2016 compared to 1983 and 1998 ( Figure S5). This also supports what researchers have previously posited, that central versus eastern based El Niños may force disparate mean midlatitude circulation responses (Feng et al, 2016;Paek et al, 2017;Yu & Kim, 2011) and thus modify CONUS precipitation responses. This pattern is also reminiscent of recent work by Siler et al (2017), which linked the dry 2015-2016 El Niño in California to enhanced warming in the western Pacific and reduced warming in the eastern Pacific and subtropical North Atlantic.…”

Section: Sea Surface Temperature Patterns and Potential Predictabilitysupporting

confidence: 90%

Zonal Wind Indices to Reconstruct CONUS Winter Precipitation

Farnham

Lall

2017

Geophysical Research Letters

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Seasonal precipitation forecasts over the contiguous United States (CONUS) during the 2015-2016 El Niño exhibited significant bias over many regions, especially in the western United States where seasonal information is particularly valuable for reservoir operation. Diagnosing the origin of this bias requires understanding the empirical signal from tropical heating to midlatitude precipitation. In this paper, we find that atmospheric zonal wind indices computed over the region typically associated with the winter jet stream provide a skillful, spatially distributed, linear prediction of precipitation over CONUS, over all winters (January-March; JFM). Furthermore, we show that more (less) central (eastern) Pacific Ocean heating may have contributed to the unexpected 2016 JFM CONUS precipitation and that this was likely predictable based on antecedent (December) sea surface temperatures. The zonal wind indices act as intermediate variables in a causal chain, and our analyses provide support for the potential for empirical prediction and also a diagnostic for physics-based models to help improve forecasts.

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“…These nonlinearities are driven by zonal shifts in the wave train that determines the extratropical teleconnection and are influenced by the longitudinal location of tropical Pacific convection (Cannon, ; Hoerling et al, , ; Wu et al, ) and event strength (Hoell et al, ; Hoerling & Kumar, ). There is also an increasing body of evidence suggesting that El Niño events come in different “flavors,” with markedly different climate impacts between events located in the central Pacific and eastern Pacific (Capotondi et al, ; Feng et al, ; Liang et al, ; Yu & Zou, ; Yu et al, ). However, some of these nonlinear impacts are still disputed, with some arguing that they are associated with atmospheric noise rather than a systematic, forced response (Deser et al, ).…”

Section: Discussionmentioning

confidence: 99%

Hydroclimatological Drivers of Extreme Floods on Lake Ontario

Carter

2018

Water Resources Research

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This study examines the hydrologic and climatic conditions that precede major flood events on Lake Ontario, with the purpose of understanding the potential for seasonal forecasts to inform lake level management. Seven late spring/early summer flood events are identified since 1949, including the record‐breaking flood of 2017. The surface climate, atmospheric circulation, and antecedent lake levels for the preceding winter and spring seasons are examined. Results suggest that flood events are caused by different combinations of high, initial wintertime water levels across all of the Great Lakes, anomalously wet winters across the entire Great Lakes basin, and wet spring conditions, particularly in the eastern part of the basin. Wet winters that precede flood events are often associated with La Niña conditions, while wet springs are often associated with a westward shift of the North Atlantic Subtropical High. As the critical drawdown period for Lake Ontario occurs in the fall, before the onset of anomalous winter or spring/summer inputs, a generalized additive model was used to predict April–August maximum monthly average Lake Ontario water levels using November levels for all Great Lakes, a nonlinear response to the wintertime Niño 3.4 index, and scenarios of April–May overbasin precipitation. The Niño 3.4 index significantly improves lake level predictions, suggesting that an El Niño‐Southern Oscillation signal may be useful for lake level management. Future work needed to verify the use of El Niño‐Southern Oscillation for Lake Ontario flood forecasting and to link the North Atlantic Subtropical High to predictions of springtime Great Lakes climate is discussed.

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Asymmetry of the winter extra-tropical teleconnections in the Northern Hemisphere associated with two types of ENSO

Cited by 83 publications

References 60 publications

Effects of two different La Niña types on the South American rainfall

Effects of two different La Niña types on the South American rainfall

Zonal Wind Indices to Reconstruct CONUS Winter Precipitation

Hydroclimatological Drivers of Extreme Floods on Lake Ontario

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