Seasonal heat content changes in the western Mediterranean Sea as a means for evaluating surface heat flux formulations

The Western Mediterranean Sea is often subject to intense winds, especially during the winter season. Intense winds induce surface cooling associated with anomalous ocean heat loss, upwelling and diapycnal mixing. In this study we investigate the overall impact of extreme wind events on the upper ocean in the Western Mediterranean sea using sea surface temperature and sea surface height observational data products over the period 1993–2014. We show that the largest thermal anomaly is observed a couple of days after the intense wind event and that it is dependent on the wind intensity. During winter, when deep water formation occurs, it persists for over a month. During summer, when the thermocline is very shallow, the recovery time scale is typically less than 10 days. The sea surface height signal reaches a minimum in correspondence to the intense wind, and normal conditions recover in about six weeks. Unlike for intense winds in the tropics associated to the passage of tropical cyclones, no long term sea surface height anomaly is observed, indicating that the water column heat content is not significantly modified. The observed recovery times suggest instead the possibility of feedbacks on the dynamics of intense cyclones at sub-monthly time scales.

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

Journal of Climate ◽

10.1175/2009jcli3081.1 ◽

2010 ◽

Vol 23 (1) ◽

pp. 197-206 ◽

Cited By ~ 44

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.

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Ocean signature of intense wind events in the Western Mediterranean Sea

10.5194/os-2018-95 ◽

2018 ◽

Author(s):

Francesco Ragone ◽

Andrea Meli ◽

Anna Napoli ◽

Claudia Pasquero

Keyword(s):

Mediterranean Sea ◽

Winter Season ◽

Heat Content ◽

Sea Surface Height ◽

Western Mediterranean ◽

Sea Surface ◽

Height Anomaly ◽

Surface Cooling ◽

Western Mediterranean Sea ◽

Wind Events

Abstract. The Western Mediterranean Sea is often subject to intense winds, especially during the winter season. The effects of the enhanced enthalpy and momentum fluxes on the upper ocean is investigated using sea surface temperature and sea surface height observational data products in the period 1993–2014. The maximum surface cooling associated with the anomalous ocean heat loss, with upwelling, and with diapycnal mixing is shown to occur a couple of days after the intense wind event, to be dependent on the wind intensity and to persist for over a month during winter, when deep water is formed, and for about 10 days during summer, when the thermocline is very shallow. The sea surface height signal reaches a minimum in correspondence of the intense wind, and normal conditions recover in about six weeks. Unlike for intense winds in the tropics, associated to tropical cyclones, no long term sea surface height anomaly is observed, indicating that the water column heat content is not significantly modified.

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Decadal variability of heat content in South China Sea inferred from observation data and an ocean data assimilation product

Ocean Science Discussions ◽

10.5194/osd-10-1329-2013 ◽

2013 ◽

Vol 10 (4) ◽

pp. 1329-1342

Author(s):

W. Song ◽

J. Lan ◽

Q. Liu ◽

D. Wang

Keyword(s):

Heat Flux ◽

Data Assimilation ◽

South China Sea ◽

South China ◽

Surface Heat Flux ◽

Decadal Variability ◽

Heat Content ◽

Surface Heat ◽

China Sea ◽

Ocean Data Assimilation

Abstract. Using an observation dataset of temperature and the Simple Ocean Data Assimilation (SODA), the decadal variability of upper ocean heat content (0–400 m; hereafter, OHC) in the South China Sea (SCS) was investigated for the period from 1958 to 2007. Decadal variability was identified as the dominant mode of upper OHC besides the seasonal cycle. According to deceasing or increasing OHC, four periods were chosen to discuss detailed processes behind OHC variability in the SCS; the four periods are 1958–1968, 1969–1981, 1982–1992, and 1993–2003. Results show that advection was the major factor for decreasing (increasing) OHC during 1958–1968 (1968–1981). During 1982–1992 and 1993–2003, the net surface heat flux was the main contributor to the variability of OHC besides the advection. The OHC, advection and net surface heat flux had significant rising tendencies during 1992–2003. The spatial characteristics of OHC variability and heat budget in the Luzon Strait, west of Luzon Island, and Xisha warm eddy region were also discussed in this paper.

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Budgets for Decadal Variability in Pacific Ocean Heat Content

Journal of Climate ◽

10.1175/jcli-d-19-0360.1 ◽

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.

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Ocean Heat Uptake and Interbasin Transport of the Passive and Redistributive Components of Surface Heating

Journal of Climate ◽

10.1175/jcli-d-16-0138.1 ◽

2016 ◽

Vol 29 (20) ◽

pp. 7507-7527 ◽

Cited By ~ 20

Author(s):

Oluwayemi A. Garuba ◽

Barry A. Klinger

Keyword(s):

Heat Flux ◽

Heat Input ◽

Surface Heat Flux ◽

Heat Content ◽

Surface Heat ◽

Global Ocean ◽

Passive Component ◽

Ocean Heat Uptake ◽

Anomalous Surface ◽

Heat Uptake

Abstract Global warming induces ocean circulation changes that not only can redistribute ocean reservoir temperature stratification but also change the total heat content anomaly of the ocean. Here all consequences of this process are referred to collectively as “redistribution.” Previous model studies of redistributive effects could not measure the net global contribution to the amount of ocean heat uptake by redistribution. In this study, a global ocean model experiment with abrupt increase in surface temperature is conducted with a new passive tracer formulation. This separates ocean heat uptake into contributions due to redistribution temperature and surface heat flux anomalies and those due to the passive advection and mixing of surface heat flux anomalies forced in the atmosphere. For a decline in the Atlantic meridional overturning circulation of about 40%, redistribution nearly doubles the Atlantic passive anomalous surface heat input and depth penetration of temperature anomalies. However, smaller increases in the Indian and Pacific Oceans cause the net global redistributive contribution to be only 25% of the passive contribution. Despite the much larger anomalous surface heat input in the Atlantic, the Pacific gains heat content anomaly similar to that in the Atlantic because of export from the Atlantic and Indian Oceans via the global conveyor belt. Of this interbasin heat transport, most of the passive component comes from the Indian Ocean and the redistributive component comes from the Atlantic.

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Decadal variability of heat content in the South China Sea inferred from observation data and an ocean data assimilation product

Ocean Science ◽

10.5194/os-10-135-2014 ◽

2014 ◽

Vol 10 (1) ◽

pp. 135-139 ◽

Cited By ~ 13

Author(s):

Wei Song ◽

Jian Lan ◽

Qinyan Liu ◽

Dandan Sui ◽

Lili Zeng ◽

...

Keyword(s):

Heat Flux ◽

Data Assimilation ◽

South China Sea ◽

South China ◽

Surface Heat Flux ◽

Decadal Variability ◽

Heat Content ◽

Surface Heat ◽

Observation Data ◽

Ocean Data Assimilation

Abstract. Using an observation data set of temperature and the Simple Ocean Data Assimilation (SODA), the decadal variability of upper ocean heat content (0–400 m; hereafter, OHC) in the South China Sea (SCS) was investigated for the period from 1958 to 2007. Decadal variability was identified as the dominant mode of upper OHC besides the seasonal cycle. According to decreasing or increasing OHC, four periods were chosen to discuss detailed processes behind OHC variability in the SCS; the four periods are 1958–1968, 1969–1981, 1982–1992, and 1993–2003. Results show that advection was the major factor for decreasing (increasing) OHC during 1958–1968 (1968–1981). During 1982–1992 and 1993–2003, the net surface heat flux was the main contributor to the variability of OHC besides the advection. The OHC, advection and net surface heat flux had significant positive trends during 1992–2003. The spatial characteristics of OHC variability and heat budget in the Luzon Strait, west of Luzon Island, and in the Xisha warm eddy region are also discussed.

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Analysis of significant measures for thermal conductivity

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2020-3-35-42 ◽

2020 ◽

pp. 35-42

Author(s):

Yuri P. Zarichnyak ◽

Vyacheslav P. Khodunkov

Keyword(s):

Thermal Conductivity ◽

Heat Flux ◽

Surface Heat Flux ◽

Heat Flux Density ◽

Measurement Method ◽

Conductivity Measurement ◽

Surface Heat ◽

Measuring Instrument ◽

New Class ◽

Achievable Accuracy

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.

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