Changes in the relationship in the SST variability between the tropical Pacific and the North Pacific across the 1998/1999 regime shift

Abstract Persistent, multi-year shifts in atmospheric circulations and their associated influence on regional climates have profound impacts on physical, biological, and socioeconomic systems. The Pacific Decadal Precession (PDP), an atmospheric mode of variability consisting of a lower tropospheric height dipole which rotates counterclockwise over several years in the North Pacific, describes a series of such shifts in atmospheric circulations. One phase of the PDP, the north-south (N-S) phase, is hypothesized to be partially driven by central tropical Pacific (CP) sea surface temperature (SST) variability, but robust assessment of this dynamical connection in climate models remains to be done. In this study, we investigate this hypothesis with analyses in both reanalysis and selected models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) archive. We show that the emergence of the N-S phase is both related to and influenced by tropical Pacific decadal SST variability, specifically variability associated with CP El Niño-Southern Oscillation (ENSO) events. When examining the CMIP6 model output, we find that most models cannot recover the characteristic cyclonic precession of the dipoles of the PDP, instead featuring only amplitude and sign changes of the N-S phase, Moreover, the models do not replicate the dynamical connections between the tropical Pacific and this North Pacific mode. Our results suggest that primary reasons for this inconsistency are that models inaccurately simulate both the SST pattern associated with the PDP, shared low-frequency power associated with CP ENSO events, and incorrect Rossby wavetrains emanating from the tropical Pacific into the North Pacific on quasi-decadal timescales. Taken together, our analyses offer another benchmark by which to test the fidelity of the climate model simulations in capturing Pacific decadal climate variability in order to improve decadal-to-centennial climate projections.

Download Full-text

Role of the western tropical Pacific in the North Pacific regime shift in the winter of 1998/1999

Journal of Geophysical Research Oceans ◽

10.1002/2013jc009527 ◽

2014 ◽

Vol 119 (9) ◽

pp. 6161-6170 ◽

Cited By ~ 10

Author(s):

Hyun-Su Jo ◽

Sang-Wook Yeh ◽

Ben P. Kirtman

Keyword(s):

North Pacific ◽

Regime Shift ◽

Tropical Pacific ◽

Western Tropical Pacific ◽

The North ◽

The North Pacific

Download Full-text

Pacific Decadal Variability: The Tropical Pacific Mode and the North Pacific Mode*

Journal of Climate ◽

10.1175/1520-0442(2003)16<1101:pdvttp>2.0.co;2 ◽

2003 ◽

Vol 16 (8) ◽

pp. 1101-1120 ◽

Cited By ~ 123

Author(s):

L. Wu ◽

Z. Liu ◽

R. Gallimore ◽

R. Jacob ◽

D. Lee ◽

...

Keyword(s):

North Pacific ◽

Decadal Variability ◽

Tropical Pacific ◽

The North ◽

Pacific Decadal Variability ◽

The North Pacific ◽

The Tropical Pacific

Download Full-text

The Development of a Statistical Forecast Model for Changma

Weather and Forecasting ◽

10.1175/waf-d-13-00003.1 ◽

2013 ◽

Vol 28 (6) ◽

pp. 1304-1321 ◽

Cited By ~ 24

Author(s):

Seung-Eon Lee ◽

Kyong-Hwan Seo

Keyword(s):

Wave Propagation ◽

North Atlantic ◽

North Pacific ◽

Forecast Model ◽

Tropical Pacific ◽

The North ◽

Sst Anomaly ◽

The North Atlantic ◽

The North Pacific ◽

The Tropical Pacific

Abstract Forecasting year-to-year variations in East Asian summer monsoon (EASM) precipitation is one of the most challenging tasks in climate prediction because the predictors are not sufficiently well known and the forecast skill of the numerical models is poor. In this paper, a statistical forecast model for changma (the Korean portion of the EASM system) precipitation is proposed that was constructed with three physically based predictors. A forward-stepwise regression was used to select the predictors that included sea surface temperature (SST) anomalies over the North Pacific, the North Atlantic, and the tropical Pacific Ocean. Seasonal predictions with this model showed high forecasting capabilities that had a Gerrity skill score of ~0.82. The dynamical processes associated with the predictors were examined prior to their use in the prediction scheme. All predictors tended to induce an anticyclonic anomaly to the east or southeast of Japan, which was responsible for transporting a large amount of moisture to the southern Korean Peninsula. The predictor in the North Pacific formed an SST front to the east of Japan during the summertime, which maintained a lower-tropospheric baroclinicity. The North Atlantic SST anomaly induced downstream wave propagation in the upper troposphere, developing anticyclonic activity east of Japan. Forcing from the tropical Pacific SST anomaly triggered a cyclonic anomaly over the South China Sea, which was maintained by atmosphere–ocean interactions and induced an anticyclonic anomaly via northward Rossby wave propagation. Overall, the model used for forecasting changma precipitation performed well (R = 0.85) and correctly predicted information for 16 out of 19 yr of observational data.

Download Full-text

Causal dependences between the coupled ocean-atmosphere dynamics over the Tropical Pacific, the North Pacific and the North Atlantic

10.5194/esd-2018-3 ◽

2018 ◽

Author(s):

Stéphane Vannitsem ◽

Pierre Ekelmans

Keyword(s):

North Atlantic ◽

North Pacific ◽

Thermohaline Circulation ◽

Tropical Pacific ◽

Ocean Dynamics ◽

The North ◽

Ocean Atmosphere ◽

The North Atlantic ◽

The North Pacific ◽

The Tropical Pacific

Abstract. The causal dependences between the dynamics of three different coupled ocean-atmosphere basins, The North Atlantic, the North Pacific and the Tropical Pacific region, NINO3.4, have been explored using data from three reanalyses datasets, namely the ORA-20C, the ORAS4 and the ERA-20C. The approach is based on the Convergent Cross Mapping (CCM) developed by Sugihara et al. (2012) that allows for evaluating the dependences between observables beyond the classical teleconnection patterns based on correlations. The use of CCM on these data mostly reveals that (i) the Tropical Pacific (NINO3.4 region) only influences the dynamics of the North Atlantic region through its annual climatological cycle; (ii) the atmosphere over the North Pacific is dynamically forcing the North Atlantic on a monthly basis; (iii) on longer time scales (interannual), the dynamics of the North Pacific and the North Atlantic are influencing each other through the ocean dynamics, suggesting a connection through the thermohaline circulation. These findings shed a new light on the coupling between these three different important regions of the globe. In particular they call for a deep reassessment of the way teleconnections are interpreted, and for a more rigorous way to evaluate causality and dependences between the different components of the climate system.

Download Full-text

Enhanced Relationship between Central Tropical Pacific Sea Surface Temperature and Eurasian Surface Air Temperature during Boreal Summers

Journal of Climate ◽

10.1175/jcli-d-19-0028.1 ◽

2021 ◽

pp. 1-68

Author(s):

Jing Ming ◽

Jianqi Sun

Keyword(s):

Air Temperature ◽

North Pacific ◽

Wave Train ◽

Surface Air Temperature ◽

Tropical Pacific ◽

Sea Surface ◽

The North ◽

The Relationship ◽

The North Pacific ◽

Mean State

AbstractThis study investigates the relationship between the central tropical Pacific (CTP) sea surface temperature (SST) and the surface air temperature (SAT) variability un-related to canonical El Niño-Southern Oscillation (ENSO) over mid-to-high latitude Eurasia during boreal summers over the past half-century. The results show that their relationship experienced a decadal shift around the early 1980s. Before the early 1980s, the Eurasian SAT-CTP SST connection was weak; after that time, the relationship became stronger, and the SAT anomalies exhibited a significant wave-like pattern over Eurasia. Such a decadal change in the Eurasian SAT-CTP SST relationship could be attributed to decadal changes in the mean state and variability of CTP SST. The warmer mean state and enhanced SST variability after the early 1980s reinforced the convective activities over the tropical Pacific, leading to significantly anomalous divergence/convergence and Rossby wave sources over the North Pacific. This outcome further excited the wave train propagating along the Northern Hemisphere zonal jet stream to northern Eurasia and then affected the surface heat fluxes and atmospheric circulations over the region, resulting in wave-like SATs over Eurasia. However, during the period before the early 1980s, the CTP SST had a weak impact on the North Pacific atmospheric circulation and was consequently not able to excite the wave train pattern to impact the Eurasian atmospheric circulation and SATs. The physical processes linking the CTP SST and Eurasian SAT are further confirmed by numerical simulations. The results of this study are valuable to understanding the variability of summer Eurasian SATs.

Download Full-text

Causal dependences between the coupled ocean–atmosphere dynamics over the tropical Pacific, the North Pacific and the North Atlantic

Earth System Dynamics ◽

10.5194/esd-9-1063-2018 ◽

2018 ◽

Vol 9 (3) ◽

pp. 1063-1083 ◽

Cited By ~ 6

Author(s):

Stéphane Vannitsem ◽

Pierre Ekelmans

Keyword(s):

North Atlantic ◽

North Pacific ◽

Thermohaline Circulation ◽

Tropical Pacific ◽

Ocean Dynamics ◽

The North ◽

Ocean Atmosphere ◽

The North Atlantic ◽

The North Pacific ◽

The Tropical Pacific

Abstract. The causal dependences (in a dynamical sense) between the dynamics of three different coupled ocean–atmosphere basins, the North Atlantic, the North Pacific and the tropical Pacific region (Nino3.4), have been explored using data from three reanalysis datasets, namely ORA-20C, ORAS4 and ERA-20C. The approach is based on convergent cross mapping (CCM) developed by Sugihara et al. (2012) that allows for evaluating the dependences between variables beyond the classical teleconnection patterns based on correlations. The use of CCM on these data mostly reveals that (i) the tropical Pacific (Nino3.4 region) only influences the dynamics of the North Atlantic region through its annual climatological cycle; (ii) the atmosphere over the North Pacific is dynamically forcing the North Atlantic on a monthly basis; (iii) on longer timescales (interannual), the dynamics of the North Pacific and the North Atlantic are influencing each other through the ocean dynamics, suggesting a connection through the thermohaline circulation. These findings shed a new light on the coupling between these three different regions of the globe. In particular, they call for a deep reassessment of the way teleconnections are interpreted and for a more rigorous way to evaluate dynamical dependences between the different components of the climate system.

Download Full-text