Intraseasonal variations of Ocean Heat Content in the tropical Indian and Pacific Ocean

2021 ◽  
Author(s):  
Ashneel Chandra ◽  
Noel Keenlyside ◽  
Lea Svendsen ◽  
Awnesh Singh
Keyword(s):  
Pacific Ocean ◽  
Heat Budget ◽  
Heat Content ◽  
Equatorial Pacific ◽  
Kelvin Waves ◽  
Ocean Heat Content ◽  
Equatorial Pacific Ocean ◽  
Budget Analysis ◽  
The Earth ◽  
The Indian Ocean

<p>The ocean heat content (OHC) is an important thermodynamical parameter in the Earth’s climate system as about 90% of the Earth’s Energy Imbalance (EEI) is stored in the ocean. It is therefore important to understand how this quantity varies on different timescales and how different thermodynamical and dynamical processes affect it. On intraseasonal timescales, there is a two-way interaction between the atmosphere and ocean whereby atmospheric forcing leads to ocean dynamics causing changes in OHC and OHC, in turn, possibly playing a role in affecting the intensity of the Madden-Julian Oscillation (MJO) through air-sea interactions. In this study, we focus on the variations of OHC in the equatorial Indian and Pacific Ocean on intraseasonal timescales. A heat budget analysis for the upper 100 m was performed using HYCOM Reanalysis for the period 2005 – 2015. The simple three-term heat budget comprised of a surface heat flux term <em>(Q),</em> an advection and adiabatic redistribution term <em>(ADV)</em> and finally a residual term <em>(RES)</em> to account for processes not resolved using the reanalysis product. When averaged over the equatorial Pacific Ocean, the heat budget analysis shows that the <em>ADV</em> and <em>RES</em> terms contributed the most to the ocean heat content tendency <em>(OHCT).</em> Zonal wind anomalies are observed to excite intraseasonal Kelvin waves in the equatorial Pacific Ocean. These Kelvin waves are associated with the eastward advection of intraseasonal OHC anomalies from the western Pacific warm pool to the central Pacific. This eastward propagation of intraseasonal OHC anomalies associated with Kelvin waves is seen to contribute to the warming leading to El Niño events such as the 2009 El Niño. In the Indian Ocean, intraseasonal OHC anomalies along the equator were seen to be in phase with the MJO as revealed by the negative intraseasonal outgoing longwave radiation (OLR) anomalies, while the off-equatorial intraseasonal OHC anomalies were seen to be out of phase with the MJO. Off-equatorial intraseasonal OHC anomalies in the Indian Ocean may be a useful parameter to investigate further as it may provide the residual heat energy for air-sea interactions for subsequent MJO events and hence improve subseasonal predictability.</p>

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.

Influence of penetrating solar radiation on the heat budget of the equatorial Pacific Ocean

Nature ◽  
1990 ◽  
Vol 347 (6293) ◽  
pp. 543-545 ◽  
Author(s):  
Marion R. Lewis ◽  
Mary-Elena Carr ◽  
Gene C. Feldman ◽  
Wayne Esaias ◽  
Chuck McClain
Keyword(s):  
Pacific Ocean ◽  
Solar Radiation ◽  
Heat Budget ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean

scholarly journals Modulation of Tropical Instability Wave Intensity by Equatorial Kelvin Waves

2016 ◽  
Vol 46 (9) ◽  
pp. 2623-2643 ◽  
Author(s):  
R. M. Holmes ◽  
L. N. Thomas
Keyword(s):  
Pacific Ocean ◽  
Kinetic Energy ◽  
Large Scale ◽  
Ocean Model ◽  
Equatorial Pacific ◽  
Kelvin Waves ◽  
Heat Fluxes ◽  
Instability Wave ◽  
Reynolds Stresses ◽  
Equatorial Pacific Ocean

AbstractTropical instability waves (TIWs) and equatorial Kelvin waves are dominant sources of intraseasonal variability in the equatorial Pacific Ocean, and both play important roles in the heat and momentum budgets of the large-scale flow. While individually they have been well studied, little is known about how these two features interact, although satellite observations suggest that TIW propagation speed and amplitude are modulated by Kelvin waves. Here, the influence of Kelvin waves on TIW kinetic energy (TIWKE) is examined using an ensemble set of 1/4° ocean model simulations of the equatorial Pacific Ocean. The results suggest that TIWKE can be significantly modified by 60-day Kelvin waves. To leading order, TIWs derive kinetic energy from the meridional shear and available potential energy of the background zonal currents, while losing TIWKE to friction and the radiation of waves. The passage of Kelvin waves disrupts this balance. Downwelling (upwelling) Kelvin waves induce decay (growth) in TIWKE through modifications to the background currents and the TIWs’ Reynolds stresses. These modulations in TIWKE affect eddy heat fluxes and the downward radiation of waves, with implications for the variability of SST and the energetics of abyssal flows in the eastern equatorial Pacific.

scholarly journals Budgets for Decadal Variability in Pacific Ocean Heat Content

2020 ◽  
Vol 33 (17) ◽  
pp. 7663-7678
Author(s):  
Zeyuan Hu ◽  
Aixue Hu ◽  
Yongyun Hu ◽  
Nan Rosenbloom
Keyword(s):  
Heat Flux ◽  
Pacific Ocean ◽  
Heat Transport ◽  
Surface Heat Flux ◽  
Heat Content ◽  
Surface Heat ◽  
Equatorial Pacific ◽  
Ocean Heat Content ◽  
Heat Advection ◽  
Oceanic Heat Transport

AbstractA slowdown in the rate of surface warming in the early 2000s led to renewed interest in the redistribution of ocean heat content (OHC) and its relationship with internal climate variability. We use the Community Earth System Model version 1 to study the relationship between OHC and the interdecadal Pacific oscillation (IPO), a major mode of decadal sea surface temperature variability in the Pacific Ocean. By comparing the relative contributions of surface heat flux and ocean dynamics to changes in OHC for different phases of the IPO, we try to identify the underlying physical processes involved. Our results suggest that during IPO phase transitions, changes of 0–300-m OHC across the northern extratropical Pacific are positively contributed by both surface heat flux and oceanic heat transport. By contrast, oceanic heat transport appears to drive the OHC changes in equatorial Pacific whereas surface heat flux acts as a damping term. During a positive IPO phase, weakened wind-driven circulation acts to increase the OHC in the equatorial Pacific while the enhanced evaporation acts to damp OHC anomalies. In the Kuroshio–Oyashio Extension region, a dipole anomaly of zonal heat advection amplifies an OHC dipole anomaly that moves eastward, while strong turbulent heat fluxes act to dampen this OHC anomaly. In the northern subtropical Pacific, both the wind-driven evaporation change and the change of zonal heat advection along Kuroshio Extension contribute to the OHC change during phase transition. For the northern subpolar Pacific, both surface heat flux and enhanced meridional advection contribute to the positive OHC anomalies during the positive IPO phase.

scholarly journals The Role of Ocean Dynamical Thermostat in Delaying the El Niño–Like Response over the Equatorial Pacific to Climate Warming

2017 ◽  
Vol 30 (8) ◽  
pp. 2811-2827 ◽  
Author(s):  
Yiyong Luo ◽  
Jian Lu ◽  
Fukai Liu ◽  
Oluwayemi Garuba
Keyword(s):  
Climate Warming ◽  
El Niño ◽  
El Nino ◽  
Heat Budget ◽  
Equatorial Pacific ◽  
Ocean Dynamics ◽  
Trade Wind ◽  
Equatorial Pacific Ocean ◽  
Budget Analysis

The role of ocean dynamics in the response of the equatorial Pacific Ocean to climate warming is investigated using both an atmosphere–ocean coupled climate system and its ocean component. Results show that the initial response (fast pattern) to an uniform heating imposed on the ocean is a warming centered to the west of the date line owing to the conventional ocean dynamical thermostat (ODT) mechanism in the eastern equatorial Pacific—a cooling effect arising from the up-gradient upwelling. In time, the warming pattern gradually propagates eastward, becoming more El Niño–like (slow pattern). The transition from the fast to the slow pattern likely results from 1) the gradual warming of the equatorial thermocline temperature, which is associated with the arrival of the relatively warmer extratropical waters advected along the subsurface branch of the subtropical cells (STCs), and 2) the reduction of the STC strength itself. A mixed layer heat budget analysis finds that it is the total ocean dynamical effect rather than the conventional ODT that holds the key for understanding the pattern of the SST in the equatorial Pacific and that the surface heat flux works mainly to compensate the ocean dynamics. Further passive tracer experiments with the ocean component of the coupled system verify the role of the ocean dynamical processes in initiating a La Niña–like SST warming and in setting the pace of the transition to an El Niño–like warming and identify an oceanic origin for the slow eastern Pacific warming independent of the weakening trade wind.

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