Influence of ocean tides on the general ocean circulation in the early Eocene

Weber, Tobias; Thomas, Maik

doi:10.1002/2016pa002997

Cited by 13 publications

(13 citation statements)

References 85 publications

(180 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, the difference in the MOC intensity simulated by coupled and uncoupled models could be primarily caused by the positive salt-advection feedback and the self-stabilizing thermal feedback (Sijp and England, 2004). It is noteworthy that the strengthening influence of tidal-induced mixing on the MOC (+7 Sv) is associated with a rather weak increase in OHT, lower than 0.03 PW on average, in agreement with Weber and Thomas (2017). Such a nonlinear relationship between OHT and MOC has also been suggested by Boccaletti (2005), who stressed that, locally, the shallow circulation can be as important as the deep overturning for determining the OHT.…”

Section: Oceanic Heat Transportsupporting

confidence: 66%

Early Eocene vigorous ocean overturning and its contribution to a warm Southern Ocean

Zhang¹,

Huck²,

Lique³

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. The early Eocene (~ 55 Ma) is the warmest period, and most likely characterized by the highest atmospheric CO2 concentrations, of the Cenozoic era. Here, we analyze simulations of the early Eocene performed with the IPSL-CM5A2 coupled climate model set up with paleogeographic reconstructions of this period from the DeepMIP project, with different levels of atmospheric CO2, and compare them with simulations of the modern conditions. This allows us to explore the changes of the ocean circulation and the resulting ocean meridional heat transport. At a CO2 level of 840 ppm, the Early Eocene simulation is characterized by a strong abyssal overturning circulation in the Southern Hemisphere (40 Sv at 60º S), fed by deep water formation in the three sectors of the Southern Ocean. Deep convection in the Southern Ocean is favored by the closed Drake and Tasmanian passages, which provide western boundaries for the build-up of strong subpolar gyres in the Weddell and Ross seas, in the middle of which convection develops. The strong overturning circulation, associated with the subpolar gyres, sustains the poleward advection of saline subtropical water to the convective region in the Southern Ocean, maintaining deep-water formation. This salt-advection feedback mechanism works similarly in the present-day North Atlantic overturning circulation. The strong abyssal overturning circulation in the 55 Ma simulations primarily results in an enhanced poleward ocean heat transport by 0.3–0.7 PW in the Southern Hemisphere compared to modern conditions, reaching 1.7 PW southward at 20° S, and contributing to maintain the Southern Ocean and Antarctica warm in the Eocene. Simulations with different atmospheric CO2 levels show that the ocean circulation and heat transport are relatively insensitive to CO2-doubling.

show abstract

Section: Oceanic Heat Transportsupporting

confidence: 66%

Early Eocene vigorous ocean overturning and its contribution to a warm Southern Ocean

Zhang¹,

Huck²,

Lique³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…In agreement with some previous early Eocene simulations (Alexander et al., 2015; Heinze & Ilyina, 2015; Huber & Sloan, 2001; Weber & Thomas, 2017), our 55 Ma simulation (with the mid‐latitude seaway opened) also simulates a strong AMOC, though this result does not agree with geological reconstructions. The δ 13 C and ε Nd evidence indicates that the Southern Ocean deep water dominates the thermohaline circulation in the early Paleogene (e.g., Abbott et al., 2016; Batenburg et al., 2018; Robinson & Vance, 2012; Thomas et al., 2003).…”

Section: Discussionsupporting

confidence: 87%

Potential Role of Mid‐Latitude Seaway on Early Paleogene Atlantic Overturning Circulation

Zhu

Zhang

Zhu

et al. 2023

Geophysical Research Letters

View full text Add to dashboard Cite

The proto-Paratethys was a vast east-west oriented inland sea within mid-latitudes during the Cretaceous to Paleogene times, which extended across Eurasia from western Europe to the Tarim Basin in western China (Kaya et al., 2018;Radionova et al., 2003; Figure 1a). From the early Eocene to the Oligocene, the sea experienced longterm regression, superimposed by major transgression-regression cycles due to tectonic and/or eustatic effects (Kaya et al., 2018;Meijer et al., 2019;Radionova et al., 2003). At its eastern end, the transgressive and regressive intervals of the proto-Paratethys are clearly recorded in the Tarim Basin and coincide with the humid and arid phases, respectively in the Qaidam and Xining basins, demonstrating the role of the proto-Paratethys as an important moisture source for the Asian interior (Bosboom et al., 2014;Kaya et al., 2018). Modeling studies also suggest that the westward retreat of the proto-Paratethys could strengthen the Asian monsoons by enlarging the land-sea thermal contrast (Ramstein et al., 1997;Z. Zhang et al., 2007).Besides, the sea level fluctuations of the proto-Paratethys could alter the seaways between the proto-Paratethys and the adjacent oceans (Iakovleva, 2011;Kaya et al., 2018;Radionova et al., 2003). During the early Paleogene, there are two potential connections of the proto-Paratethys with the mid-and high-latitude oceans: one is westward through the Polish Lowland Basin to the North Sea and the North Atlantic; the other is northward through the Turgai Strait to the West Siberia Sea and the Arctic (Figure 1a). The correlation of sediment facies across the proto-Paratethys area suggests that in the late Paleocene and the early Eocene, the two open connections ensured an extensive water exchange between the proto-Paratethys and the Arctic (Iakovleva, 2011;Radionova et al., 2003). Further studies revealed largely similar microfossil assemblages between the proto-Paratethys and the North Sea, confirming that these two basins were indeed connected during the early Eocene (Deprez et al., 2015;King et al., 2013). It seems that the exchange of water masses between the proto-Paratethys and the Arctic via the

show abstract

“…Montenegro et al () indicate negligible effects of LGM tides on the AMOC, whereas Schmittner et al () report a substantial strengthening and deepening of the overturning cell in the North Atlantic. There have been some attempts to model tides and ocean circulation in an ocean model setup that explicitly models tidal dynamics at the same resolution as the ocean general circulation (see, e.g., Müller et al, ; Müller et al, , Weber & Thomas, ). However, the tide models in these configurations either are less accurate due to their low resolution or else at higher resolution; the computational expense of the ocean model becomes prohibitive for multimillenial length simulations necessary for the LGM.…”

Section: Introductionmentioning

confidence: 99%

Glacial Ice Sheet Extent Effects on Modeled Tidal Mixing and the Global Overturning Circulation

Wilmes

Schmittner

Green

2019

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

At present, tides supply approximately half (1 TW) of the energy necessary to sustain the global deep meridional overturning circulation (MOC) through diapycnal mixing. During the Last Glacial Maximum (LGM; 19,000–26,500 years BP), tidal dissipation in the open ocean may have strongly increased due to the 120‐ to 130‐m global mean sea level drop and changes in ocean basin shape. However, few investigations into LGM climate and ocean circulation consider LGM tidal mixing changes. Here, using an intermediate complexity climate model, we present a detailed investigation on how changes in tidal dissipation would affect the global MOC. Present‐day and LGM tidal constituents M2, S2, K1, and O1 are simulated using a tide model and accounting for LGM bathymetric changes. The tide model results suggest that the LGM energy supply to the internal wave field was 1.8–3 times larger than at present and highly sensitive to Antarctic and Laurentide ice sheet extent. Including realistic LGM tide forcing in the LGM climate simulations leads to large increases in Atlantic diapycnal diffusivities and strengthens (by 14–64% at 32°S) and deepens the Atlantic MOC. Increased input of tidal energy leads to a greater drawdown of North Atlantic Deep Water and mixing with Antarctic Bottom Water altering Atlantic temperature and salinity distributions. Our results imply that changes in tidal dissipation need be accounted for in paleoclimate simulation setup as they can lead to large differences in ocean mixing, the global MOC, and presumably also ocean carbon and other biogeochemical cycles.

show abstract

Influence of ocean tides on the general ocean circulation in the early Eocene

Cited by 13 publications

References 85 publications

Early Eocene vigorous ocean overturning and its contribution to a warm Southern Ocean

Early Eocene vigorous ocean overturning and its contribution to a warm Southern Ocean

Potential Role of Mid‐Latitude Seaway on Early Paleogene Atlantic Overturning Circulation

Glacial Ice Sheet Extent Effects on Modeled Tidal Mixing and the Global Overturning Circulation

Contact Info

Product

Resources

About