The characteristics of signal versus noise sst variability in the north pacific and the tropical pacific ocean

Abstract In this paper, global climatic response to the North Pacific oceanic warming is investigated in a series of coupled ocean–atmosphere modeling experiments. In the model, an idealized heating is imposed over the North Pacific Ocean, while the ocean and atmosphere remain fully coupled both locally and elsewhere. The model explicitly demonstrates that the North Pacific oceanic warming can force a significant change of the atmospheric circulation with a strong seasonal dependence. The seasonal marching of the atmospheric response over the North Pacific is characterized by a quasi-baratropic warm ridge in early winter, a transition to a quasi-baratropic warm trough in late winter, and then to a baroclinic response in summer with a trough and ridge, respectively, in the lower and upper troposphere. The North Pacific warming also forces a significant remote response over the tropical Pacific. In winter, the tropical Pacific response is characterized by a nearly uniform warming coupled with anomalous southerly cross-equatorial winds, while in summer it is dominated by an enhanced zonal SST gradient and anomalous equatorial easterlies. The tropical warming tends to be associated with a reduction of the upper-ocean meridional overturning circulation and equatorial ocean dynamics associated with a reduction of the Hadley circulation and the surface coupled wind–evaporation–SST feedback. The resulting tropical warming can further intensify the seasonal marching of the North Pacific atmospheric response. The global impacts of the North Pacific warming are also discussed.

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The influence of decadal oscillations on the oxygen and nutrient trends in the Pacific Ocean

10.5194/bg-2019-91 ◽

2019 ◽

Author(s):

Lothar Stramma ◽

Sunke Schmidtko ◽

Steven J. Bograd ◽

Tsuneo Ono ◽

Tetjana Ross ◽

...

Keyword(s):

Pacific Ocean ◽

North Pacific ◽

Tropical Pacific ◽

Ocean Warming ◽

The North ◽

The Pacific ◽

Major Mode ◽

The Pacific Ocean ◽

The North Pacific ◽

The Tropical Pacific

Abstract. A strong oxygen deficient layer is located in the upper layer of the tropical Pacific Ocean and at deeper depths in the North Pacific. Processes related to climate change (upper ocean warming, reduced ventilation) are expected to change ocean oxygen and nutrient inventories. In most ocean basins, a decrease in oxygen (‘deoxygenation’) and an increase of nutrients has been observed in subsurface layers. Deoxygenation trends are not linear and there could be other influences on oxygen and nutrient trends and variability. Here oxygen and nutrient time series since 1950 in the Pacific Ocean were investigated at 50 to 300 m depth, as this layer provides critical pelagic habitat for biological communities. In addition to trends related to ocean warming the oxygen and nutrient trends show a strong influence of the Pacific Decadal Oscillation (PDO) in the tropical and the eastern Pacific, and the North Pacific Gyre Oscillation (NPGO) especially in the North Pacific. In the Oyashio Region the PDO, the NPGO, the North Pacific Index (NPI) and a 18.6 year nodal tidal cycle overlay the long-term trend. In most regions oxygen increases and nutrients decrease in the 50 to 300 m layer during the negative PDO phase, with opposite trends during the positive PDO phase. The PDO index encapsulates the major mode of surface temperature variability in the Pacific and oxygen and nutrients trends throughout the basin can be described in the context of the PDO phases. An influence of the subtropical-tropical cell in the tropical Pacific cannot be proven with the available data. El Niño and La Niña years often influence the oxygen and nutrient distribution during the event in the eastern tropical Pacific, but do not have a multi-year influence on the trends.

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The Pacific Decadal Precession and its Relationship to Tropical Pacific Decadal Variability in CMIP6 Models

10.21203/rs.3.rs-390152/v1 ◽

2021 ◽

Author(s):

Matthew H. Rogers ◽

Jason Furtado ◽

Bruce Anderson

Keyword(s):

North Pacific ◽

Tropical Pacific ◽

S Phase ◽

Atmospheric Circulations ◽

Enso Events ◽

The North ◽

Sst Variability ◽

The Pacific ◽

The North Pacific ◽

The Tropical Pacific

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.

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Sensitivity study of the tropical Pacific precipitation anomalies

10.5194/nhess-2016-83 ◽

2016 ◽

Author(s):

Shouwen Zhang ◽

Hua Jiang ◽

Hui Wang ◽

Ling Du ◽

Dakui Wang

Keyword(s):

Pacific Ocean ◽

Sea Ice ◽

North Atlantic ◽

Climate Model ◽

Tropical Pacific ◽

Tropical Pacific Ocean ◽

The North ◽

Precipitation Anomalies ◽

The North Atlantic ◽

The Tropical Pacific

Abstract. Climate model results have shown that precipitation in the tropical Pacific Ocean will change up to 15 % and 25 % in one century. In this paper, both reanalysis data and climate model are used to study the response of global ocean and atmosphere to precipitation anomalies in the tropical Pacific Ocean. It shows that positive precipitation anomalies could trigger an El Nino-like SSTA response, with warmer SST in the east tropical Pacific Ocean and slightly cooler SST in the west tropical Pacific Ocean. The zonal tropical ocean currents change significantly, of which the magnitudes and directions are mainly relying on the intensity of the precipitation anomalies. Through a wave train encompassing the whole Northern Hemisphere named as the Circumglobal Waveguide Pattern (CWP), the North Atlantic atmospheric circulation responds to the freshwater anomalies in a NAO-like pattern. The anomalous atmospheric circulation transport sea ice to the North Atlantic Ocean. The sea ice melts in summer and freshen the upper ocean, which makes the ocean more stable. It thus constrains vertical heat transport and makes the upper water cooler, forming a significant positive feedback mechanism.

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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

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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.

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Decadal changes in the relationship between the tropical Pacific and the North Pacific

Journal of Geophysical Research Atmospheres ◽

10.1029/2012jd017775 ◽

2012 ◽

Vol 117 (D15) ◽

pp. n/a-n/a ◽

Cited By ~ 11

Author(s):

Sae-Rim Yeo ◽

Kwang-Yul Kim ◽

Sang-Wook Yeh ◽

WonMoo Kim

Keyword(s):

North Pacific ◽

Tropical Pacific ◽

The North ◽

The Relationship ◽

The North Pacific ◽

The Tropical Pacific

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Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific

Biogeosciences ◽

10.5194/bg-17-813-2020 ◽

2020 ◽

Vol 17 (3) ◽

pp. 813-831

Author(s):

Lothar Stramma ◽

Sunke Schmidtko ◽

Steven J. Bograd ◽

Tsuneo Ono ◽

Tetjana Ross ◽

...

Keyword(s):

Pacific Ocean ◽

North Pacific ◽

Tropical Pacific ◽

Ocean Warming ◽

Eastern Pacific ◽

Nutrient Distribution ◽

The North ◽

The Pacific ◽

Major Mode ◽

The North Pacific

Abstract. A strong oxygen-deficient layer is located in the upper layers of the tropical Pacific Ocean and deeper in the North Pacific. Processes related to climate change (upper-ocean warming, reduced ventilation) are expected to change ocean oxygen and nutrient inventories. In most ocean basins, a decrease in oxygen (“deoxygenation”) and an increase in nutrients have been observed in subsurface layers. Deoxygenation trends are not linear and there could be multiple influences on oxygen and nutrient trends and variability. Here oxygen and nutrient time series since 1950 in the Pacific Ocean were investigated at 50 to 300 m depth, as this layer provides critical pelagic habitat for biological communities. In addition to trends related to ocean warming the oxygen and nutrient trends show a strong influence of the Pacific Decadal Oscillation (PDO) in the tropical and the eastern Pacific, and the North Pacific Gyre Oscillation (NPGO) in particular in the North Pacific. In the Oyashio Region the PDO, the NPGO, the North Pacific Index (NPI) and an 18.6-year nodal tidal cycle overlay the long-term trend. In most eastern Pacific regions oxygen increases and nutrients decrease in the 50 to 300 m layer during the negative PDO phase, with opposite trends during the positive PDO phase. The PDO index encapsulates the major mode of sea surface temperature variability in the Pacific, and oxygen and nutrients trends throughout the basin can be described in the context of the PDO phases. El Niño and La Niña years often influence the oxygen and nutrient distribution during the event in the eastern tropical Pacific but do not have a multi-year influence on the trends.

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