scholarly journals Role of Equatorial Pacific SST Forecast Error in the Late Winter California Precipitation Forecast for the 2015/16 El Niño

2018 ◽  
Vol 31 (2) ◽  
pp. 839-852 ◽  
Author(s):  
Bor-Ting Jong ◽  
Mingfang Ting ◽  
Richard Seager ◽  
Naomi Henderson ◽  
Dong Eun Lee
Keyword(s):  
El Niño ◽  
El Nino ◽  
Forecast Error ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Precipitation Forecast ◽  
Late Winter ◽  
Eastern Tropical Pacific ◽  
The North ◽  
Ensemble Mean

During the strong 2015/16 El Niño, only normal to below-average precipitation fell across California in the late winter. This disagrees with both predictions by the ensemble mean of forecast models and expectations for strong El Niños. The authors examine one of the possible reasons why this event did not bring expected precipitation to California in the late winter. The maximum equatorial Pacific sea surface temperature anomalies (SSTAs) were located, compared to the 1982/83 and 1997/98 strong El Niños, farther to the west in the 2015/16 winter, which possibly caused less convection in the eastern tropical Pacific and shifted the teleconnection patterns westward in the North Pacific, thus weakening the influences on California. The SSTA and precipitation forecast for February–April 2016, based on the North American Multimodel Ensemble, showed large discrepancies from observations, with the ensemble mean of most of the models overestimating SSTAs in the eastern tropical Pacific and California precipitation. Atmospheric general circulation model (AGCM) experiments were conducted to test the hypothesis that the warmer eastern tropical Pacific SSTA forecast may have caused the wetter forecast in California in 2015/16 compared to observations. The AGCM experiments suggest it is difficult to assert that the eastern tropical Pacific SSTAs caused the too-wet California precipitation forecast, especially in Southern California, given that the models disagree. Results indicate forecast error can be influenced by atmosphere-model sensitivity to forecast SSTs, but they also indicate atmospheric internal variability may have been responsible for the combination of a strong El Niño and near-normal California precipitation.

scholarly journals A Nonstationary ENSO–NAO Relationship Due to AMO Modulation

2018 ◽  
Vol 32 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Wenjun Zhang ◽  
Xuebin Mei ◽  
Xin Geng ◽  
Andrew G. Turner ◽  
Fei-Fei Jin
Keyword(s):  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Circulation Model ◽  
La Niña ◽  
Late Winter ◽  
The North ◽  
La Nina ◽  
The North Atlantic

Abstract Many previous studies have demonstrated a high uncertainty in the relationship between El Niño–Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). In the present work, decadal modulation by the Atlantic multidecadal oscillation (AMO) is investigated as a possible cause of the nonstationary ENSO–NAO relationship based on observed and reanalysis data. It is found that the negative ENSO–NAO correlation in late winter is significant only when ENSO and the AMO are in phase (AMO+/El Niño and AMO−/La Niña). However, no significant ENSO-driven atmospheric anomalies can be observed over the North Atlantic when ENSO and the AMO are out of phase (AMO−/El Niño and AMO+/La Niña). Further analysis indicates that the sea surface temperature anomaly (SSTA) in the tropical North Atlantic (TNA) plays an essential role in this modulating effect. Because of broadly analogous TNA SSTA responses to both ENSO and the AMO during late winter, a warm SSTA in the TNA is evident when El Niño occurs during a positive AMO phase, resulting in a significantly weakened NAO, and vice versa when La Niña occurs during a negative AMO phase. In contrast, neither the TNA SSTA nor the NAO shows a prominent change under out-of-phase combinations of ENSO and AMO. The AMO modulation and the associated effect of the TNA SSTA are shown to be well reproduced by historical simulations of the HadCM3 coupled model and further verified by forced experiments using an atmospheric circulation model. These offer hope that similar models will be able to make predictions for the NAO when appropriately initialized.

scholarly journals The 2015-2016 El Niño increased infection parameters of copepods on Eastern Tropical Pacific dolphinfish populations

PLoS ONE ◽  
2020 ◽  
Vol 15 (5) ◽  
pp. e0232737
Author(s):  
Ana María Santana-Piñeros ◽  
Yanis Cruz-Quintana ◽  
Ana Luisa May-Tec ◽  
Geormery Mera-Loor ◽  
María Leopoldina Aguirre-Macedo ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Eastern Tropical Pacific ◽  
Infection Parameters

Model Biases in the Simulation of the Springtime North Pacific ENSO Teleconnection

2020 ◽  
Vol 33 (23) ◽  
pp. 9985-10002
Author(s):  
Ruyan Chen ◽  
Isla R. Simpson ◽  
Clara Deser ◽  
Bin Wang
Keyword(s):  
El Niño ◽  
North Pacific ◽  
Climate Models ◽  
El Nino ◽  
Coupled Model ◽  
La Niña ◽  
Late Winter ◽  
The North ◽  
La Nina ◽  
The North Pacific

AbstractThe wintertime ENSO teleconnection over the North Pacific region consists of an intensified (weakened) low pressure center during El Niño (La Niña) events both in observations and in climate models. Here, it is demonstrated that this teleconnection persists too strongly into late winter and spring in the Community Earth System Model (CESM). This discrepancy arises in both fully coupled and atmosphere-only configurations, when observed SSTs are specified, and is shown to be robust when accounting for the sampling uncertainty due to internal variability. Furthermore, a similar problem is found in many other models from piControl simulations of the Coupled Model Intercomparison Project (23 out of 43 in phase 5 and 11 out of 20 in phase 6). The implications of this bias for the simulation of surface climate anomalies over North America are assessed. The overall effect on the ENSO composite field (El Niño minus La Niña) resembles an overly prolonged influence of ENSO into the spring with anomalously high temperatures over Alaska and western Canada, and wet (dry) biases over California (southwest Canada). Further studies are still needed to disentangle the relative roles played by diabatic heating, background flow, and other possible contributions in determining the overly strong springtime ENSO teleconnection intensity over the North Pacific.

El Nino and little ice age effects on upwelling in the eastern tropical pacific

1988 ◽  
Vol 70 (1-2) ◽  
pp. 198
Author(s):  
C.T. Shen ◽  
R.B. Dunbar ◽  
M.W. Colgan ◽  
P.W. Glynn
Keyword(s):  
El Niño ◽  
Little Ice Age ◽  
El Nino ◽  
Tropical Pacific ◽  
Age Effects ◽  
Ice Age ◽  
Eastern Tropical Pacific

Mid-Holocene El Niño–Southern Oscillation (ENSO) attenuation revealed by individual foraminifera in eastern tropical Pacific sediments

Geology ◽  
2006 ◽  
Vol 34 (12) ◽  
pp. 993 ◽  
Author(s):  
Athanasios Koutavas ◽  
Peter B. deMenocal ◽  
George C. Olive ◽  
Jean Lynch-Stieglitz
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Tropical Pacific ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Eastern Tropical Pacific

scholarly journals Reproduction of the blue-footed booby predicts commercial fish abundance in the eastern tropical Pacific

2013 ◽  
Vol 70 (6) ◽  
pp. 1263-1272
Author(s):  
Juan Meraz ◽  
Sergio Ancona ◽  
Cristina Rodríguez ◽  
Hugh Drummond
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Fish Abundance ◽  
Sea Surface ◽  
Eastern Tropical Pacific ◽  
Prey Fish ◽  
Commercial Fish ◽  
Local Abundance ◽  
Two Factors

Abstract Meraz, J., Ancona, S., Rodríguez, C., and Drummond, H. 2013. Reproduction of the blue-footed booby predicts commercial fish abundance in the eastern tropical Pacific. – ICES Journal of Marine Science, 70: 1263–1272. To establish whether reproduction in a colony of the blue-footed booby in the eastern tropical Pacific predicts local abundance of prey fish several months later, 13 years of data were analysed. Eight reproductive variables assessed during the period of January–May, grouped in two factors, were related to commercial catches in the surrounding 6600 km2 area during the following June–December. The first factor explained 33% of interannual variance in fish captures per unit effort during June–December (future FCUE), and 63% when only El Niño years were considered. Also, the proportion of large clutches present on three single-day censuses in the spring explained 51, 46 and 35% of variance in future FCUE among all years, and 78, 85 and 82% of variance among El Niño years. In contrast, sea surface temperatures in March did not explain variance in future FCUE. Proportion of large clutches is a moderately good predictor of the abundance of commercial fish during the subsequent seven months and can be satisfactorily and cheaply measured on a single day.

scholarly journals Oceanic Rossby Waves over Eastern Tropical Pacific of Both Hemispheres Forced by Anomalous Surface Winds after Mature Phase of ENSO

2016 ◽  
Vol 46 (11) ◽  
pp. 3397-3414 ◽  
Author(s):  
Hiroto Abe ◽  
Youichi Tanimoto ◽  
Takuya Hasegawa ◽  
Naoto Ebuchi
Keyword(s):  
Rossby Wave ◽  
El Niño ◽  
Rossby Waves ◽  
El Nino ◽  
Tropical Pacific ◽  
Sea Surface ◽  
Eastern Coast ◽  
Eastern Tropical Pacific ◽  
Enso Events ◽  
Anomalous Surface

AbstractThe present study examined ENSO-related wind forcing contribution to off-equatorial Rossby wave formations in the eastern tropical regions of the North and South Pacific using satellite altimeter data and atmospheric reanalysis data during the period of 1993–2013. After mature phases of ENSO events, the sea surface height anomaly fields showed that off-equatorial Rossby waves propagated westward along 11°N and 8°S from the eastern Pacific. Starting longitudes of the westward propagation were distant from the eastern coast, especially for weak El Niño events in the 2000s, in contrast to the strong 1997/98 El Niño event in which the propagations started from the coast. Based on observational data, it was hypothesized that the Rossby waves could be formed by off-equatorial zonal belts of wind stress curl anomalies (WSCAs) in 135°–90°W rather than by wave emissions from the eastern coast. A numerical model forced only by WSCAs, that is, without wave emissions from the coast, successfully reproduced observed features of the Rossby waves in 180°–120°W, supporting the study’s hypothesis. During mature phases of El Niño events, equatorially symmetric negative sea level pressure anomalies (SLPAs) resulting from hydrostatic adjustment to the underlying warm sea surface temperature anomalies dominated over the eastern tropical Pacific. Anomalous surface easterlies blowing around the negative SLPA area as geostrophic winds were a major contributor in forming the anticyclonic WSCAs. The polarity of the anomalies is reversed during La Niña events. Therefore, spatial patterns of the SLPAs associated with the ENSO events are necessary to understand the Rossby wave formations.

Influence of Tropical Pacific Sea Surface Temperature on the Genesis of Gulf Stream Cyclones

2016 ◽  
Vol 73 (10) ◽  
pp. 4203-4214 ◽  
Author(s):  
Sebastian Schemm ◽  
Laura M. Ciasto ◽  
Camille Li ◽  
Nils Gunnar Kvamstø
Keyword(s):  
North Atlantic ◽  
El Niño ◽  
Gulf Stream ◽  
El Nino ◽  
Tropical Pacific ◽  
Cp El Niño ◽  
The North ◽  
Sst Variability ◽  
Ep El Niño ◽  
The North Atlantic

Abstract This study investigates the relationship between tropical Pacific sea surface temperature (SST) variability and cyclogenesis over the Gulf Stream region of the North Atlantic. A cyclone identification scheme and Lagrangian trajectories are used to compare preferred cyclogenesis locations and precyclogenesis flow paths associated with three patterns of tropical Pacific SST variability: eastern Pacific (EP) El Niño, central Pacific (CP) El Niño, and La Niña. During EP El Niño and La Niña winters, the upper-level precyclogenesis flow takes a subtropical path over North America and Gulf Stream cyclogenesis predominantly occurs under the North Atlantic jet entrance, which is the climatologically preferred location. In contrast, during CP El Niño winters, when the warmest SST anomalies occur in the central tropical Pacific, the precyclogenesis flow takes a northern path across North America and Gulf Stream cyclogenesis tends to occur farther north under the jet exit. The shift in preferred cyclogenesis is consistent with changes in transient upstream flow perturbations, detected using potential vorticity (PV) streamer frequencies, which are associated with the stationary wave response. Compared to EP El Niño winters, CP El Niño winters exhibit fewer southward-extending streamers and cyclonic (LC2) flow behavior, resulting in precyclogenesis air bypassing the right entrance of the North Atlantic jet. Downstream, Gulf Stream cyclones penetrate deeper into high Arctic latitudes during CP El Niño winters than in other cases. The results highlight distinct signatures of tropical SST anomalies on synoptic-scale atmospheric features and could help constrain future changes in the North Atlantic storm track and the associated poleward heat transport.

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