Variation of Residual Current in the Seto Inland Sea Driven by Sea Level Difference Between the Bungo and Kii Channels

2018 ◽  
Vol 123 (4) ◽  
pp. 2921-2933 ◽  
Author(s):  
Naokazu Taniguchi ◽  
Chen-Fen Huang ◽  
Masazumi Arai ◽  
Bruce M. Howe
Keyword(s):  
Sea Level ◽  
Residual Current ◽  
Seto Inland Sea ◽  
Level Difference ◽  
The Seto Inland Sea ◽  
Sea Level Difference

Atlantic to Mediterranean Sea Level Difference Driven by Winds near Gibraltar Strait

2007 ◽  
Vol 37 (2) ◽  
pp. 359-376 ◽  
Author(s):  
Dimitris Menemenlis ◽  
Ichiro Fukumori ◽  
Tong Lee
Keyword(s):  
Mediterranean Sea ◽  
Sea Level ◽  
Wind Stress ◽  
Coastal Current ◽  
Alboran Sea ◽  
Mean Sea Level ◽  
Level Difference ◽  
Gibraltar Strait ◽  
Sea Level Difference ◽  
Alborán Sea

Abstract Observations and numerical simulations show that winds near Gibraltar Strait cause an Atlantic Ocean to Mediterranean Sea sea level difference of 20 cm peak to peak with a 3-cm standard deviation for periods of days to years. Theoretical arguments and numerical experiments establish that this wind-driven sea level difference is caused in part by storm surges due to alongshore winds near the North African coastline on the Atlantic side of Gibraltar. The fraction of the Moroccan coastal current offshore of the 284-m isobath is deflected across Gibraltar Strait, west of Camarinal Sill, resulting in a geostrophic surface pressure gradient that contributes to a sea level difference at the stationary limit. The sea level difference is also caused in part by the along-strait wind setup, with a contribution proportional to the along-strait wind stress and to the length of Gibraltar Strait and adjoining regions and inversely proportional to its depth. In the 20–360-day band, average transfer coefficients between the Atlantic–Alboran sea level difference and surface wind stress at 36°N, 6.5°W, estimated from barometrically corrected Ocean Topography Experiment (TOPEX)/Poseidon data and NCEP–NCAR reanalysis data, are 0.10 ± 0.04 m Pa−1 with 1 ± 5-day lag and 0.19 ± 0.08 m Pa−1 with 5 ± 4-day lag for the zonal and meridional wind stresses, respectively. This transfer function is consistent with equivalent estimates derived from a 1992–2003 high-resolution barotropic simulation forced by the NCEP–NCAR wind stress. The barotropic simulation explains 29% of the observed Atlantic–Alboran sea level difference in the 20–360-day band. In turn, the Alboran and Mediterranean mean sea level time series are highly correlated, ρ = 0.7 in the observations and ρ = 0.8 in the barotropic simulation, hence providing a pathway for winds near Gibraltar Strait to affect the mean sea level of the entire Mediterranean.

scholarly journals On the relation between Meridional Overturning Circulation and sea-level gradients in the Atlantic

2012 ◽  
Vol 3 (1) ◽  
pp. 325-356 ◽  
Author(s):  
H. Kienert ◽  
S. Rahmstorf
Keyword(s):  
Sea Level ◽  
Co2 Concentration ◽  
Meridional Overturning Circulation ◽  
Overturning Circulation ◽  
Simultaneous Application ◽  
Level Difference ◽  
Ocean Winds ◽  
Meridional Overturning ◽  
The Individual ◽  
Sea Level Difference

Abstract. On the basis of model simulations, we examine what information on changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) can be extracted from associated changes in sea surface height (SSH), specifically from a broad Atlantic north-south gradient as has been suggested previously in the literature. Since a relation between AMOC and SSH changes can only be used as an AMOC diagnostic if it is valid independently of the specific forcing, we consider three different forcing types: increase of CO2 concentration, freshwater fluxes to the northern convection sites and the modification of Southern Ocean winds. We concentrate on a timescale of 100 yr. We find approximately linear and numerically similar relations between a sea-level difference within the Atlantic and the AMOC for freshwater as well as wind forcing. However, the relation is more complex in response to atmospheric CO2 increase, which precludes this sea-level difference as an AMOC diagnostic under climate change. Finally, we show qualitatively to what extent changes in SSH and AMOC strength that are caused by simultaneous application of different forcings correspond to the sum of the changes due to the individual forcings, a potential prerequisite for more complex SSH-based AMOC diagnostics.

scholarly journals On the relation between Meridional Overturning Circulation and sea-level gradients in the Atlantic

2012 ◽  
Vol 3 (2) ◽  
pp. 109-120 ◽  
Author(s):  
H. Kienert ◽  
S. Rahmstorf
Keyword(s):  
Sea Level ◽  
Co2 Concentration ◽  
Meridional Overturning Circulation ◽  
Overturning Circulation ◽  
Simultaneous Application ◽  
Level Difference ◽  
Ocean Winds ◽  
Meridional Overturning ◽  
The Individual ◽  
Sea Level Difference

Abstract. On the basis of model simulations, we examine what information on changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) can be extracted from associated changes in sea surface height (SSH), specifically from a broad Atlantic north–south gradient as has been suggested previously in the literature. Since a relation between AMOC and SSH changes can only be used as an AMOC diagnostic if it is valid independently of the specific forcing, we consider three different forcing types: increase of CO2 concentration, freshwater fluxes to the northern convection sites and the modification of Southern Ocean winds. We concentrate on a timescale of 100 yr. We find approximately linear and numerically similar relations between a sea-level difference within the Atlantic and the AMOC for freshwater as well as wind forcing. However, the relation is more complex in response to atmospheric CO2 increase, which precludes this sea-level difference as an AMOC diagnostic under climate change. Finally, we show qualitatively to what extent changes in SSH and AMOC strength, which are caused by simultaneous application of different forcings, correspond to the sum of the changes due to the individual forcings, a potential prerequisite for more complex SSH-based AMOC diagnostics.

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