Deconstructing Atlantic Intertropical Convergence Zone variability: Influence of the local cross-equatorial sea surface temperature gradient and remote forcing from the eastern equatorial Pacific

2002 ◽  
Vol 107 (D1) ◽  
Author(s):  
John C. H. Chiang
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Equatorial Pacific ◽  
Intertropical Convergence Zone ◽  
Sea Surface ◽  
Convergence Zone ◽  
Remote Forcing ◽  
Eastern Equatorial Pacific ◽  
Sea Surface Temperature Gradient ◽  
Surface Temperature Gradient

What Controls the Mean East–West Sea Surface Temperature Gradient in the Equatorial Pacific: The Role of Cloud Albedo

2014 ◽  
Vol 27 (7) ◽  
pp. 2757-2778 ◽  
Author(s):  
N. J. Burls ◽  
A. V. Fedorov
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Walker Circulation ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Sea Surface Temperature Gradient ◽  
The Mean ◽  
East West ◽  
Surface Temperature Gradient

Abstract The mean east–west sea surface temperature gradient along the equator is a key feature of tropical climate. Tightly coupled to the atmospheric Walker circulation and the oceanic east–west thermocline tilt, it effectively defines tropical climate conditions. In the Pacific, its presence permits the El Niño–Southern Oscillation phenomenon. What determines this temperature gradient within the fully coupled ocean–atmosphere system is therefore a central question in climate dynamics, critical for understanding past and future climates. Using a comprehensive coupled model [Community Earth System Model (CESM)], the authors demonstrate how the meridional gradient in cloud albedo between the tropics and midlatitudes (Δα) sets the mean east–west sea surface temperature gradient in the equatorial Pacific. To change Δα in the numerical experiments, the authors change the optical properties of clouds by modifying the atmospheric water path, but only in the shortwave radiation scheme of the model. When Δα is varied from approximately −0.15 to 0.1, the east–west SST contrast in the equatorial Pacific reduces from 7.5°C to less than 1°C and the Walker circulation nearly collapses. These experiments reveal a near-linear dependence between Δα and the zonal temperature gradient, which generally agrees with results from the Coupled Model Intercomparison Project phase 5 (CMIP5) preindustrial control simulations. The authors explain the close relation between the two variables using an energy balance model incorporating the essential dynamics of the warm pool, cold tongue, and Walker circulation complex.

scholarly journals Enhanced warming constrained by past trends in equatorial Pacific sea surface temperature gradient

2020 ◽  
Vol 11 (1) ◽  
pp. 33-37
Author(s):  
Masahiro Watanabe ◽  
Jean-Louis Dufresne ◽  
Yu Kosaka ◽  
Thorsten Mauritsen ◽  
Hiroaki Tatebe
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Sea Surface Temperature Gradient ◽  
Surface Temperature Gradient

scholarly journals Decoupling of temperature and pH gradients along the equatorial Pacific during the Pliocene

2020 ◽  
Author(s):  
Pincelli Hull ◽  
Madison Shankle ◽  
Natalie Burls ◽  
Alexey Fedorov ◽  
Matthew Thomas ◽  
...  
Keyword(s):  
Global Warming ◽  
Temperature Gradient ◽  
Surface Temperature ◽  
Southern Oscillation ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Biological Productivity ◽  
Sea Surface Temperature Gradient ◽  
East West ◽  
Surface Temperature Gradient

Abstract Equatorial Pacific dynamics drive tropical climate patterns such as the El Niño-Southern Oscillation and provide nutrients for one of the world’s most productive marine ecosystems. How this region will respond to global warming remains an important area of study with profound implications for both human wellbeing and economic and ecosystem stability. In light of this, numerous studies have investigated equatorial Pacific dynamics during the Pliocene epoch (5.3-2.6 million years ago) as an analogue for future behavior of the region under global warming (1–12). Current paleoceanographic records from the Pliocene tropical Pacific present an apparent paradox, with proxy evidence of a reduced east-west sea surface temperature gradient along the equator(1,5,6,11)– indicative of reduced wind-driven upwelling – conflicting with evidence of enhanced biological productivity in the region (13–15) which is typically driven by upwelling. Here we reconcile these observations by providing new evidence for older, more acidic, and nutrient-rich water reaching the equatorial Pacific by way of a Pacific meridional overturning cell during the Pliocene (16). This provides a mechanism by which enhanced productivity could have existed alongside a reduced east-west sea surface temperature gradient in the Pliocene equatorial Pacific. Furthermore, these results challenge the current paradigm of a decline in biological productivity in warmer worlds due to enhanced thermal stratification (17). Our findings shed a new light on equatorial Pacific dynamics and help constrain potential changes to them in the near-future, given that the Earth is expected to reach Pliocene-like temperatures by the end of the century. The equatorial Pacific is a region of great significance as it hosts one of the most important climate phenomena on the planet, the El Niño Southern Oscillation (18), and supports massively productive fisheries that provide key ecosystem services to numerous communities (19,20), and our results provide novel insight on how it might change as the oceans adjust to a warming world.

scholarly journals The role of the meridional sea surface temperature gradient in controlling the Caribbean low‐level jet

2017 ◽  
Vol 122 (11) ◽  
pp. 5903-5916 ◽  
Author(s):  
Tito Maldonado ◽  
Anna Rutgersson ◽  
Rodrigo Caballero ◽  
Francesco S. R. Pausata ◽  
Eric Alfaro ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Low Level ◽  
Sea Surface Temperature Gradient ◽  
Low Level Jet ◽  
The Caribbean ◽  
Surface Temperature Gradient

scholarly journals The West Pacific Gradient tracks ENSO and zonal Pacific sea surface temperature gradient during the last Millennium

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. Zinke ◽  
S. A. Browning ◽  
A. Hoell ◽  
I. D. Goodwin
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Nino ◽  
Sea Surface ◽  
Last Millennium ◽  
The West ◽  
West Pacific ◽  
Sea Surface Temperature Gradient ◽  
Surface Temperature Gradient

AbstractSmall changes in Pacific temperature gradients connected with the El Niño Southern Oscillation (ENSO) influence the Walker Circulation and are related to global climate anomalies. Therefore, it is of paramount importance to develop robust indices of their past behavior. Here, we reconstruct the difference in sea surface temperature between the west and central Pacific during ENSO, coined the West Pacific Gradient (WPG), based on the Last Millennium Paleo Hydrodynamics Data Assimilation. We show that the WPG tracks ENSO variability and strongly co-varies with the zonal gradient in Pacific sea surface temperature. We demonstrate that the WPG strength is related to significant atmospheric circulation and precipitation anomalies during historical El Niño and La Niña events by magnifying or weakening droughts and pluvials across the Indo-Pacific. We show that an extreme negative WPG coupled to a strong zonal Pacific temperature gradient is associated with enhanced megadroughts in North America between 1400 CE and the late sixteenth century. The twentieth century stands out in showing the most extreme swings between positive and negative WPG conditions over the past Millennium. We conclude that the WPG is a robust index together with ENSO indices to reveal past changes in Pacific zonal sea surface temperature gradient variability.

Sign in / Sign up

Export Citation Format

Share Document