scholarly journals Tropical Pacific Ocean Dynamical Response to Short-Term Sulfate Aerosol Forcing

2019 ◽  
Vol 32 (23) ◽  
pp. 8205-8221
Author(s):  
Tarun Verma ◽  
R. Saravanan ◽  
P. Chang ◽  
S. Mahajan
Keyword(s):  
Pacific Ocean ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Sulfate Aerosol ◽  
Upper Ocean ◽  
Sulfate Aerosols ◽  
Tropical Pacific Ocean ◽  
Aerosol Forcing ◽  
Ocean Atmosphere ◽  
The Tropical Pacific

Abstract The large-scale and long-term climate impacts of anthropogenic sulfate aerosols consist of Northern Hemisphere cooling and a southward shift of the tropical rain belt. On interannual time scales, however, the response to aerosols is localized with a sizable imprint on local ocean–atmosphere interaction. A large concentration of anthropogenic sulfates over Asia may impact ENSO by modifying processes and interactions that generate this coupled ocean–atmosphere variability. Here, we use climate model experiments with different degrees of ocean–atmosphere coupling to study the tropical Pacific response to an abrupt increase in anthropogenic sulfates. These include an atmospheric general circulation model (GCM) coupled to either a full-ocean GCM or a slab-ocean model, or simply forced by climatology of sea surface temperature. Comparing the responses helps differentiate between the fast atmospheric and slow ocean-mediated responses, and highlights the role of ocean–atmosphere coupling in the latter. We demonstrate the link between the Walker circulation and the equatorial Pacific upper-ocean dynamics in response to increased sulfate aerosols. The local surface cooling due to sulfate aerosols emitted over the Asian continent drives atmospheric subsidence over the equatorial west Pacific. The associated anomalous circulation imparts westerly momentum to the underlying Pacific Ocean, leading to an El Niño–like upper-ocean response and a transient warming of the east equatorial Pacific Ocean. The oceanic adjustment eventually contributes to its decay, giving rise to a damped oscillation of the tropical Pacific Ocean in response to abrupt anthropogenic sulfate aerosol forcing.

scholarly journals Forcing of the Indian Ocean Dipole on the Interannual Variations of the Tropical Pacific Ocean: Roles of the Indonesian Throughflow

2011 ◽  
Vol 24 (14) ◽  
pp. 3593-3608 ◽  
Author(s):  
Dongliang Yuan ◽  
Jing Wang ◽  
Tengfei Xu ◽  
Peng Xu ◽  
Zhou Hui ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Indonesian Throughflow ◽  
Tropical Pacific Ocean ◽  
Equatorial Pacific Ocean ◽  
The Indian Ocean ◽  
The Tropical Pacific

Abstract Controlled numerical experiments using ocean-only and ocean–atmosphere coupled general circulation models show that interannual sea level depression in the eastern Indian Ocean during the Indian Ocean dipole (IOD) events forces enhanced Indonesian Throughflow (ITF) to transport warm water from the upper-equatorial Pacific Ocean to the Indian Ocean. The enhanced transport produces elevation of the thermocline and cold subsurface temperature anomalies in the western equatorial Pacific Ocean, which propagate to the eastern equatorial Pacific to induce significant coupled evolution of the tropical Pacific oceanic and atmospheric circulation. Analyses suggest that the IOD-forced ITF transport anomalies are about the same amplitudes as those induced by the Pacific ENSO. Results of the coupled model experiments suggest that the anomalies induced by the IOD persist in the equatorial Pacific until the year following the IOD event, suggesting the importance of the oceanic channel in modulating the interannual climate variations of the tropical Pacific Ocean at the time lag beyond one year.

The three-dimensional structure of an upper ocean vortex in the tropical Pacific Ocean

Nature ◽  
1996 ◽  
Vol 383 (6601) ◽  
pp. 610-613 ◽  
Author(s):  
Pierre J. Flament ◽  
Sean C. Kennan ◽  
Robert A. Knox ◽  
Pearn P. Niiler ◽  
Robert L. Bernstein
Keyword(s):  
Pacific Ocean ◽  
Three Dimensional ◽  
Tropical Pacific ◽  
Dimensional Structure ◽  
Upper Ocean ◽  
Tropical Pacific Ocean ◽  
Three Dimensional Structure ◽  
The Tropical Pacific

Origin of upper-ocean warming and El Niño change on decadal scales in the tropical Pacific Ocean

Nature ◽  
10.1038/36081 ◽  
1998 ◽  
Vol 391 (6670) ◽  
pp. 879-883 ◽  
Author(s):  
Rong-Hua Zhang ◽  
Lewis M. Rothstein ◽  
Antonio J. Busalacchi
Keyword(s):  
Pacific Ocean ◽  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Ocean Warming ◽  
Upper Ocean ◽  
Tropical Pacific Ocean ◽  
The Tropical Pacific

scholarly journals The Equatorial Thermocline Outcropping—A Seasonal Control on the Tropical Pacific Ocean–Atmosphere Instability Strength

2002 ◽  
Vol 15 (19) ◽  
pp. 2721-2739 ◽  
Author(s):  
Eli Galanti ◽  
Eli Tziperman ◽  
Matthew Harrison ◽  
Antony Rosati ◽  
Ralf Giering ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Tropical Pacific ◽  
Tropical Pacific Ocean ◽  
Equatorial Thermocline ◽  
Ocean Atmosphere ◽  
The Tropical Pacific

Improved Representation of Tropical Pacific Ocean–Atmosphere Dynamics in an Intermediate Complexity Climate Model

2014 ◽  
Vol 27 (1) ◽  
pp. 168-185 ◽  
Author(s):  
Ryan L. Sriver ◽  
Axel Timmermann ◽  
Michael E. Mann ◽  
Klaus Keller ◽  
Hugues Goosse
Keyword(s):  
Pacific Ocean ◽  
Surface Temperature ◽  
Climate Model ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Temperature Variability ◽  
Tropical Pacific Ocean ◽  
Intermediate Complexity ◽  
Ocean Atmosphere ◽  
Perturbed Physics

Abstract A new anomaly coupling technique is introduced into a coarse-resolution dynamic climate model [the Liège Ocean Carbon Heteronomous model (LOCH)–Vegetation Continuous Description model (VECODE)–Earth System Models of Intermediate Complexity Climate deBilt (ECBILT)–Coupled Large-Scale Ice–Ocean model (CLIO)–Antarctic and Greenland Ice Sheet Model (AGISM) ensemble (LOVECLIM)], improving the model’s representation of eastern equatorial Pacific surface temperature variability. The anomaly coupling amplifies the surface diabatic atmospheric forcing within a Gaussian-shaped patch applied in the tropical Pacific Ocean. It is implemented with an improved predictive cloud scheme based on empirical relationships between cloud cover and key state variables. Results are presented from a perturbed physics ensemble systematically varying the parameters controlling the anomaly coupling patch size, location, and amplitude. The model’s optimal parameter combination is chosen through calibration against the observed power spectrum of monthly-mean surface temperature anomalies in the Niño-3 region. The calibrated model exhibits substantial improvement in equatorial Pacific interannual surface temperature variability and robustly reproduces El Niño–Southern Oscillation (ENSO)-like variability. The authors diagnose some of the key atmospheric and oceanic feedbacks in the model important for simulating ENSO-like variability, such as the positive Bjerknes feedback and the negative heat flux feedback, and analyze the recharge–discharge of the equatorial Pacific ocean heat content. They find LOVECLIM robustly captures important ocean dynamics related to thermocline adjustment and equatorial Kelvin waves. The calibrated model demonstrates some improvement in simulating atmospheric feedbacks, but the coupling between ocean and atmosphere is relatively weak. Because of the tractability of LOVECLIM and its consequent utility in exploring long-term climate variability and large ensemble perturbed physics experiments, improved representation of tropical Pacific ocean–atmosphere dynamics in the model may more readily allow for the investigation of the role of tropical Pacific ocean–atmosphere dynamics in past climate changes.

scholarly journals The Effect of the Galápagos Islands on the Equatorial Pacific Cold Tongue

2007 ◽  
Vol 37 (5) ◽  
pp. 1266-1281 ◽  
Author(s):  
Kristopher B. Karnauskas ◽  
Raghu Murtugudde ◽  
Antonio J. Busalacchi
Keyword(s):  
Pacific Ocean ◽  
General Circulation ◽  
Galapagos Islands ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Cold Tongue ◽  
Galápagos Islands ◽  
Tropical Pacific Ocean ◽  
Central Pacific ◽  
The Tropical Pacific

Abstract A reduced-gravity ocean general circulation model of the tropical Pacific Ocean is used to determine potential improvements to the simulated equatorial Pacific cold tongue region through choices in horizontal resolution and coastline geometry—in particular, for the Galápagos Islands. Four simulations are performed, with identical climatological forcing. Results are compared between model grids with and without the Galápagos Islands, with coarse and fine resolutions. It is found that properly including the Galápagos Islands results in the obstruction of the Equatorial Undercurrent (EUC), which leads to improvements in the simulated spatial structure of the cold tongue, including a basinwide warming of up to 2°C in the east-central Pacific. The obstruction of the EUC is directly related to the improvements east of the Galápagos Islands, and for the basinwide reduction of the tropical cold bias through an equatorial dynamical adjustment. The pattern of SST warming resulting from the inclusion of the Galápagos Islands is similar to that of the known cold biases in ocean models and the current National Oceanic and Atmospheric Administration Climate Forecast System. It is thought that such an improvement would have a considerable impact on the ability of coupled ocean–atmosphere and ocean–ecosystem models to produce realistic clouds, precipitation, surface ocean bioproductivity, and carbon cycling in the tropical Pacific Ocean.

A Comparison of Climate Prediction and Simulation over the Tropical Pacific

2008 ◽  
Vol 21 (14) ◽  
pp. 3601-3611 ◽  
Author(s):  
Vasubandhu Misra ◽  
L. Marx ◽  
M. Fennessy ◽  
B. Kirtman ◽  
J. L. Kinter
Keyword(s):  
Pacific Ocean ◽  
Climate Model ◽  
Coupled Model ◽  
Tropical Pacific ◽  
Ocean Dynamics ◽  
Upper Ocean ◽  
Model Errors ◽  
Tropical Pacific Ocean ◽  
Operating Modes ◽  
The Tropical Pacific

Abstract This study compares an ensemble of seasonal hindcasts with a multidecadal integration from the same global coupled climate model over the tropical Pacific Ocean. It is shown that the annual mean state of the SST and its variability are different over the tropical Pacific Ocean in the two operating modes of the model. These differences are symptoms of an inherent difference in the physics of coupled air–sea interactions and upper ocean variability. It is argued that in the presence of large coupled model errors and in the absence of coupled data assimilation, the competing and at times additive influence of the initialization and model errors can change the behavior of the air–sea interaction physics and upper ocean dynamics.

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