scholarly journals Global Modes of Sea Surface Temperature Variability in Relation to Regional Climate Indices

2011 ◽  
Vol 24 (16) ◽  
pp. 4314-4331 ◽  
Author(s):  
Monique Messié ◽  
Francisco Chavez
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Regional Climate ◽  
Sea Surface ◽  
El Niño Modoki ◽  
The North ◽  
The Pacific ◽  
Global Modes ◽  
The North Pacific

Abstract A century-long EOF analysis of global sea surface temperature (SST) was carried out and the first six modes, independent by construction, were found to be associated with well-known regional climate phenomena: the El Niño–Southern Oscillation (ENSO), the Atlantic multidecadal oscillation (AMO), the Pacific decadal oscillation (PDO), the North Pacific Gyre Oscillation (NPGO), El Niño Modoki, and the Atlantic El Niño. Four of the six global modes are dominated by Pacific changes, the other two (M2 and M6) being associated with the AMO and Atlantic El Niño, respectively. The principal component time series of the ENSO (M1) and North Pacific (M3) modes are coherent at time scales >10 yr, and their interaction results in the traditional PDO pattern and the dominant mode of Pacific multidecadal variability. The M3 and PDO time series are well correlated, but the EOFs have different spatial patterns. The fourth mode (M4) has been strengthening since the 1950s and is related to the NPGO but also to El Niño Modoki, especially at the decadal scale. The fifth global mode (M5) is also spatially and temporally correlated to El Niño Modoki. The Pacific SST modes are further related to atmospheric forcing and the circulation of the North Pacific subpolar and subtropical gyres.

Evaluation of performance of CMIP5 models in simulating the North Pacific Oscillation and El Niño Modoki

2018 ◽  
Vol 52 (3-4) ◽  
pp. 1383-1394 ◽  
Author(s):  
Xin Wang ◽  
Mengyan Chen ◽  
Chunzai Wang ◽  
Sang-Wook Yeh ◽  
Wei Tan
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Cmip5 Models ◽  
North Pacific Oscillation ◽  
El Niño Modoki ◽  
The North ◽  
Evaluation Of Performance ◽  
The North Pacific

scholarly journals Attenuation of Central Pacific El Niño Amplitude by North Pacific Sea Surface Temperature Anomalies

2020 ◽  
Vol 33 (15) ◽  
pp. 6673-6688 ◽  
Author(s):  
Kang Xu ◽  
Chi-Yung Tam ◽  
Boqi Liu ◽  
Sheng Chen ◽  
Xiaoyi Yang ◽  
...  
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Sea Surface ◽  
Central Pacific ◽  
Cp El Niño ◽  
The North ◽  
Sea Surface Temperature Anomalies ◽  
Ep El Niño ◽  
The North Pacific

AbstractThere exists a pronounced asymmetry between the amplitudes of central Pacific (CP) and eastern Pacific (EP) El Niño sea surface temperature anomalies (SSTA). The present study examines such an asymmetry and its relationship with the North Pacific SSTA. Results indicate that the weaker CP El Niño amplitude can be attributed to the weaker anomalous zonal wind response to the east–west equatorial SSTA gradient during its growing phase compared with EP El Niño. Furthermore, the occurrence of CP El Niño is closely associated with southwesterly surface wind anomalies in the subtropical North Pacific, as well as ocean warming reminiscent of the North Pacific Gyre Oscillation (NPGO) pattern in its vicinity. Both the observations as well as the pacemaker experiments with a coupled global climate model suggest that the anomalous low-level southwesterlies, induced by the North Pacific Oscillation (NPO)-like atmospheric variability, can enhance anomalously positive SST signals and extend them southwestward to the central equatorial Pacific via the wind–evaporation–SST feedback. This will further attenuate the atmospheric response to zonal SSTA gradient, and hence weaken the amplitude of CP El Niño. Therefore, anomalous low-level southwesterlies over the subtropical North Pacific can effectively act as a conduit for tropical–subtropical air–sea interaction in that region, and can play an important role in limiting the intensity of CP El Niño.

The Influence of ENSO on the Generation of Decadal Variability in the North Pacific*

2007 ◽  
Vol 20 (4) ◽  
pp. 667-680 ◽  
Author(s):  
Soon-Il An ◽  
Jong-Seong Kug ◽  
Axel Timmermann ◽  
In-Sik Kang ◽  
Oliver Timm
Keyword(s):  
El Niño ◽  
North Pacific ◽  
Decadal Variability ◽  
El Nino ◽  
Sea Surface ◽  
Diagnostic Study ◽  
Sea Surface Temperatures ◽  
The North ◽  
Surface Temperatures ◽  
The North Pacific

Abstract This diagnostic study explores the generation of decadal variability in the North Pacific resulting from the asymmetry of the El Niño–Southern Oscillation phenomenon and the nonlinearity of the atmospheric tropical–extratropical teleconnection. Nonlinear regression analysis of the North Pacific sea surface temperatures and atmospheric fields with respect to the ENSO index reveals that the main teleconnection centers shift between El Niño and La Niña years. This asymmetry in the ENSO response, together with the skewed probabilistic distribution of ENSO itself, may contribute to the generation of the long-term decadal variability of sea surface temperatures in the extratropical North Pacific. It is argued that this hypothesis may explain the significant variance of the observed Pacific decadal oscillation in the extratropics.

Future Changes to El Niño Teleconnections over the North Pacific and North America

2021 ◽  
pp. 1-43
Author(s):  
Jonathan D. Beverley ◽  
Matthew Collins ◽  
F. Hugo Lambert ◽  
Robin Chadwick
Keyword(s):  
North America ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Positive Temperature ◽  
Central Pacific ◽  
Wave Source ◽  
The North ◽  
Precipitation Anomalies ◽  
The North Pacific

AbstractThe El Niño-Southern Oscillation (ENSO) is the leading mode of interannual climate variability and it exerts a strong influence on many remote regions of the world, for example in northern North America. Here, we examine future changes to the positive-phase ENSO teleconnection to the North Pacific/North America sector and investigate the mechanisms involved. We find that the positive temperature anomalies over Alaska and northern North America that are associated with an El Niño event in the present day are much weaker, or of the opposite sign, in the CMIP6 abrupt 4×CO2 experiments for almost all models (22 out of 26, of which 15 are statistically significant differences). This is largely related to changes to the anomalous circulation over the North Pacific, rather than differences in the equator-to-pole temperature gradient. Using a barotropic model, run with different background circulation basic states and Rossby wave source forcing patterns from the individual CMIP6 models, we find that changes to the forcing from the equatorial central Pacific precipitation anomalies are more important than changes in the global basic state background circulation. By further decomposing this forcing change into changes associated with the longitude and magnitude of ENSO precipitation anomalies, we demonstrate that the projected overall eastward shift of ENSO precipitation is the main driver of the temperature teleconnection change, rather than the increase in magnitude of El Niño precipitation anomalies which are, nevertheless, seen in the majority of models.

scholarly journals An Extratropical Air–Sea Interaction over the North Pacific in Association with a Preceding El Niño Episode in Early Summer

2009 ◽  
Vol 137 (11) ◽  
pp. 3771-3785 ◽  
Author(s):  
Yafei Wang ◽  
Anthony R. Lupo
Keyword(s):  
Wave Propagation ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Wave Train ◽  
The North ◽  
Rossby Wave Propagation ◽  
Okhotsk High ◽  
Wave Flux ◽  
The North Pacific

Abstract Using data for the month of June from 1951 through 2000, this study examined the air–sea interactions over the North Pacific after El Niño matured during the preceding fall season. The principal findings of this work are the following: 1) a coherent region near the international date line (IDL) in the extratropical North Pacific revealed an area of significant negative correlations (SNCs) between the preceding November sea surface temperature (SST) in the Niño-3 region and the June SST in the North Pacific. Also, two indexes of the June Okhotsk high show a significant positive correlation with the November SST in the Niño-3 region during the 1963–2000 period. 2) The strong southeastward wave flux from the upstream area of the Okhotsk Sea over much of the North Pacific in the midlatitudes is associated with a strong preceding El Niño event, the development of the Okhotsk high, and a negative 500-hPa geopotential height/SST anomaly around the coherent region. The stationary wave propagation plays a major part in maintaining the low SSTs in the coherent region and suppressing the northward progress of the subtropical high. This process partially bridges the connection between the central equatorial Pacific warming (CEPW) and the East Asian summer monsoon. 3) A wave train–like anomaly in the SST (tilted northwest–southeast) was established and maintained in the North Pacific during the summer of 1998. This coincided with the direction of the atmospheric Rossby wave propagation as the strong southeastward wave flux was scattered over the midlatitude North Pacific. This event provides solid evidence that Rossby wave propagation plays an important role in forming an oceanic temperature wave train in the extratropical Pacific through the barotropic process.

The North Pacific Pacemaker Effect on Historical ENSO and Its Mechanisms

2019 ◽  
Vol 32 (22) ◽  
pp. 7643-7661 ◽  
Author(s):  
Dillon J. Amaya ◽  
Yu Kosaka ◽  
Wenyu Zhou ◽  
Yu Zhang ◽  
Shang-Ping Xie ◽  
...  
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Southern Oscillation ◽  
Deep Convection ◽  
Boreal Summer ◽  
Enso Events ◽  
The North ◽  
The North Pacific

Abstract Studies have indicated that North Pacific sea surface temperature (SST) variability can significantly modulate El Niño–Southern Oscillation (ENSO), but there has been little effort to put extratropical–tropical interactions into the context of historical events. To quantify the role of the North Pacific in pacing the timing and magnitude of observed ENSO, we use a fully coupled climate model to produce an ensemble of North Pacific Ocean–Global Atmosphere (nPOGA) SST pacemaker simulations. In nPOGA, SST anomalies are restored back to observations in the North Pacific (>15°N) but are free to evolve throughout the rest of the globe. We find that the North Pacific SST has significantly influenced observed ENSO variability, accounting for approximately 15% of the total variance in boreal fall and winter. The connection between the North and tropical Pacific arises from two physical pathways: 1) a wind–evaporation–SST (WES) propagating mechanism, and 2) a Gill-like atmospheric response associated with anomalous deep convection in boreal summer and fall, which we refer to as the summer deep convection (SDC) response. The SDC response accounts for 25% of the observed zonal wind variability around the equatorial date line. On an event-by-event basis, nPOGA most closely reproduces the 2014/15 and the 2015/16 El Niños. In particular, we show that the 2015 Pacific meridional mode event increased wind forcing along the equator by 20%, potentially contributing to the extreme nature of the 2015/16 El Niño. Our results illustrate the significant role of extratropical noise in pacing the initiation and magnitude of ENSO events and may improve the predictability of ENSO on seasonal time scales.

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.

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