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.

Surface heat fluxes in the Western Equatorial Pacific Ocean

1995 ◽  
Vol 13 (10) ◽  
pp. 1047-1053 ◽  
Author(s):  
N. C. Wells
Keyword(s):  
Heat Flux ◽  
Pacific Ocean ◽  
Latent Heat ◽  
Longwave Radiation ◽  
Surface Heat ◽  
Equatorial Pacific ◽  
Heat Fluxes ◽  
Equatorial Pacific Ocean ◽  
Net Heat Flux ◽  
Western Equatorial Pacific

Abstract. Estimates of the components of the surface heat flux in the Western Equatorial Pacific Ocean are presented for a 22-day period, together with a critical analysis of the errors. It is shown that the errors in latent heat, and solar and longwave radiation fluxes, dominate the net heat flux for this period. It is found that the net heat flux into the ocean over the 22-day period is not significantly different from zero. It is also demonstrated that because of the variability in daily averaged values of solar radiation and the latent heat of evaporation, a large number of independent flux measurements will be required to determine with confidence the climatological net heat flux in this region. The variability of latent fluxes over the 22-day period suggest that climatological estimates based on monthly mean observations may lead to a significant underestimate of the latent heat flux.

scholarly journals Simulations of Processes Associated with the Fast Warming Rate of the Southern Midlatitude Ocean

2010 ◽  
Vol 23 (1) ◽  
pp. 197-206 ◽  
Author(s):  
Wenju Cai ◽  
Tim Cowan ◽  
Stuart Godfrey ◽  
Susan Wijffels
Keyword(s):  
Twentieth Century ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Heat Content ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Ekman Transport ◽  
Content Increase ◽  
Intergovernmental Panel ◽  
Zonal Distribution

Abstract Significant warming has occurred across many of the world’s oceans throughout the latter part of the twentieth-century. The increase in the oceanic heat content displays a considerable spatial difference, with a maximum in the 35°–50°S midlatitude band. The relative importance of wind and surface heat flux changes in driving the warming pattern is the subject of much debate. Using wind, oceanic temperature, and heat flux outputs from twentieth-century multimodel experiments, conducted for the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), the authors were able to reproduce the fast, deep warming in the midlatitude band; however, this warming is unable to be accounted for by local heat flux changes. The associated vertical structure and zonal distribution are consistent with a Sverdrup-type response to poleward-strengthening winds, with a poleward shift of the Southern Hemisphere (SH) supergyre and the Antarctic Circumpolar Current. However, the shift is not adiabatic and involves a net oceanic heat content increase over the SH, which can only be forced by changes in the net surface heat flux. Counterintuitively, the heat required for the fast, deep warming is largely derived from the surface heat fluxes south of 50°S, where the surface flux into the ocean is far larger than that of the midlatitude band. The heat south of 50°S is advected northward by an enhanced northward Ekman transport induced by the poleward-strengthening winds and penetrates northward and downward along the outcropping isopycnals to a depth of over 1000 m. However, because none of the models resolve eddies and given that eddy fluxes could offset the increase in the northward Ekman transport, the heat source for the fast, deep warming in the midlatitude band could be rather different in the real world.

scholarly journals Change of the Global Ocean Vertical Heat Transport over 1993–2010

2017 ◽  
Vol 30 (14) ◽  
pp. 5319-5327 ◽  
Author(s):  
Xinfeng Liang ◽  
Christopher G. Piecuch ◽  
Rui M. Ponte ◽  
Gael Forget ◽  
Carl Wunsch ◽  
...  
Keyword(s):  
Heat Flux ◽  
Heat Exchange ◽  
Heat Transport ◽  
Heat Content ◽  
Ocean Heat Content ◽  
Global Ocean ◽  
Mixing Processes ◽  
State Estimate ◽  
Vertical Heat ◽  
Vertical Heat Flux

A dynamically and data-consistent ocean state estimate during 1993–2010 is analyzed for bidecadal changes in the mechanisms of heat exchange between the upper and lower oceans. Many patterns of change are consistent with prior studies. However, at various levels above 1800 m the global integral of the change in ocean vertical heat flux involves the summation of positive and negative regional contributions and is not statistically significant. The nonsignificance of change in the global ocean vertical heat transport from an ocean state estimate that provides global coverage and regular sampling, spatially and temporally, raises the question of whether an adequate observational database exists to assess changes in the upper ocean heat content over the past few decades. Also, whereas the advective term largely determines the spatial pattern of the change in ocean vertical heat flux, its global integral is not significantly different from zero. In contrast, the diffusive term, although regionally weak except in high-latitude oceans, produces a statistically significant extra downward heat flux during the 2000s. This result suggests that besides ocean advection, ocean mixing processes, including isopycnal and diapycnal as well as convective mixing, are important for the decadal variation of the heat exchange between upper and deep oceans as well. Furthermore, the analyses herein indicate that focusing on any particular region in explaining changes of the global ocean heat content is misleading.

scholarly journals Subtropics-Related Interannual Sea Surface Temperature Variability in the Central Equatorial Pacific

2010 ◽  
Vol 23 (11) ◽  
pp. 2869-2884 ◽  
Author(s):  
Jin-Yi Yu ◽  
Hsun-Ying Kao ◽  
Tong Lee
Keyword(s):  
Heat Flux ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Sst Variability ◽  
Central Equatorial Pacific ◽  
Sst Anomalies

Abstract Interannual sea surface temperature (SST) variability in the central equatorial Pacific consists of a component related to eastern Pacific SST variations (called Type-1 SST variability) and a component not related to them (called Type-2 SST variability). Lead–lagged regression and ocean surface-layer temperature balance analyses were performed to contrast their control mechanisms. Type-1 variability is part of the canonical, which is characterized by SST anomalies extending from the South American coast to the central Pacific, is coupled with the Southern Oscillation, and is associated with basinwide subsurface ocean variations. This type of variability is dominated by a major 4–5-yr periodicity and a minor biennial (2–2.5 yr) periodicity. In contrast, Type-2 variability is dominated by a biennial periodicity, is associated with local air–sea interactions, and lacks a basinwide anomaly structure. In addition, Type-2 SST variability exhibits a strong connection to the subtropics of both hemispheres, particularly the Northern Hemisphere. Type-2 SST anomalies appear first in the northeastern subtropical Pacific and later spread toward the central equatorial Pacific, being generated in both regions by anomalous surface heat flux forcing associated with wind anomalies. The SST anomalies undergo rapid intensification in the central equatorial Pacific through ocean advection processes, and eventually decay as a result of surface heat flux damping and zonal advection. The southward spreading of trade wind anomalies within the northeastern subtropics-to-central tropics pathway of Type-2 variability is associated with intensity variations of the subtropical high. Type-2 variability is found to become stronger after 1990, associated with a concurrent increase in the subtropical variability. It is concluded that Type-2 interannual variability represents a subtropical-excited phenomenon that is different from the conventional ENSO Type-1 variability.

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