Abstract
Residual, or tidally averaged, circulation in fjords is generally assumed to be density driven and two layered. This circulation consists of a thin surface layer of outflow and a thick bottom layer of sluggish inflow. However, development of different vertical structures in residual circulation in fjords can arise from wind, remote, and tidal forcing that may modify the two-layer circulation. Particularly, theoretical results of tidal residual flows in homogeneous semienclosed basins indicate that their vertical structure is determined by the dynamical depth of the system. This dynamical depth can be considered as the ratio between the water column depth and the depth of frictional influence in an oscillatory flow (inverse of Stokes number). When the frictional depth occupies the entire water column, the tidal residual flow is one layered as in shallow basins. But when the frictional depth is only a small portion of the water column (>6 times smaller), the tidal residual is three layered. In relatively deep fjords (say deeper than 100 m), where frictional depths typically occupy a small portion of the water column, the tidal residual flow is expected to be three layered. Ample observational evidence presented here shows a three-layered exchange flow structure in fjords. On the basis of observational and theoretical evidence, it is proposed that the water exchange structure in deep fjords (more than six frictional layers deep, or inverse Stokes number >6) is tidally driven and is three layered. The tidally driven three-layer structure of residual flows could be regarded in some cases as the fundamental structure. However, this structure will only be observed sporadically as it will be masked by wind forcing, remote forcing from the ocean, and freshwater pulses.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Arneborg L (2004) Turnover times for the water above sill level in Gullmar Fjord. Cont Shelf Res 24:443–460
Cáceres M, Valle-Levinson A, Sepulveda H, Holderied K (2002) Transverse variability of flow and density in a Chilean fjord. Cont Shelf Res 22:1683–1698
Cáceres M, Valle-Levinson A, Fierro J, Valenzuela C, Castillo M (2010a) Variabilidad transversal del flujo y de la densidad en la boca del Fiordo Aysén. Ciencia y Tecnología del Mar 33(1):5–15
Cáceres M, Valle-Levinson A, Belmar J, Bello M, Castillo M (2010b) Variabilidad transversal del flujo y salinidad en Paso Nao. Ciencia y Tecnología del Mar 33(2):45–58
Castillo M, Bello M, Reyes H, Guerrero Y (2006) Patrones de corrientes y distribución vertical de temperatura y salinidad en la entrada oceánica del Canal Darwin en invierno y primavera de 2002. Ciencia y Tecnología del Mar 29(2):5–21
Castillo M, Pizarro O, Cifuentes U, Ramirez N, Djurfeldt L (2012) Subtidal dynamics in a deep fjord of southern Chile. Cont Shelf Res 49:73–89
Chao S-Y, Boicourt WC, Wang HVC (1996) Three-layered circulation in reverse estuaries. Cont Shelf Res 16(10):1379–1397
Dyer, K. R. (1997), Estuaries, a physical introduction 2nd Edition, Wiley, 195 pp.
Geyer WR, Cannon G (1982) Sill processes related to deep water renewal in a fjord. J Geophys Res 87:7985–7996
Huijts KMH, Schuttelaars HM, de Swart HE, Friedrichs CT (2009) Analytical study of the transverse distribution of along-channel and transverse residual flows in tidal estuaries. Cont Shelf Res 29:89–100. doi:10.1016/j.csr. 2007.09.007
Ianniello J (1977) Tidally induced residual currents in estuaries of constant breadth and depth. J Mar Res 35(4):755–786
Joyce T (1989) On in situ “calibration” of shipboard ADCPs. Journal of Atmopheric and Oceanic Technology 6:169–172
Klinck JM, O’Brien JJ, Svendsen H (1981) A simple model of fjord and coastal circulation interaction. J Phys Oceanogr 11:1612–1626
Li C, O’Donnell J (2005) The effect of channel length on the residual circulation in tidally dominated channels. J Phys Oceanogr 35:1826–1840
Officer CB (1976) Physical oceanography of estuaries. Wiley, New York, 465 pp
Rippeth TP, Simpson JH (1998) Diurnal signals in vertical motions on the Hebridean Shelf. Limnol Oceanogr 43:1690–1696
Stigebrandt A (2012) Hydrodynamics and circulation of fjords. In: Bengtsson et al (eds) Encyclopedia of Lakes and Reservoirs. Springer, Netherlands, pp 327–244
Straneo F, Hamilton GS, Sutherland DA, Stearns LA, Davidson F, Hammil MO, Stenson GB, Rosing-Asvid A (2010) Rapid circulation of warm subtropical waters in a major, East Greenland glacial fjord. Nat Geosci 3:182–186
Stucchi DJ, Bell WH (1980) Shelf-fjord exchange on the west coast of Vancouver Island. Trans Amer Geophys Union 61:280
Svendsen H, Thompson RORY (1978) Wind-driven circulation in a fjord. J Phys Oceanogr 8:703–712
Thomson RE, Mihály SF, Kulikov EA (2007) Estuarine versus transient flow regimes in Juan de Fuca Strait. J Geophys Res 112:C09022. doi:10.1029/2006JC003925
Trump CL, Marmorino G (1997) Calibrating a gyrocompass using ADCP and DGPS data. J Atmos Ocean Technol 14:211–214
Valle-Levinson A (2008) Density-driven exchange flow in terms of the Kelvin and Ekman numbers. J Geophys Res 113:C04001. doi:10.1029/2007JC004144
Valle-Levinson A, Atkinson LP (1999) Spatial gradients in the flow over an estuarine channel. Estuaries 22(2A):179–193
Valle-Levinson A, Sarkar N, Sanay R, Soto D, León J (2007) Spatial structure of hydrography and flow in a Chilean Fjord, Estuario Reloncaví. Estuar Coasts 30(1):113–126
Valle-Levinson A, Jara F, Molinet C, Soto D (2001) Observations of intratidal variability of exchange flows cver a sill/contraction combination in a Chilean fjord. J Geophys Res 106(C4):7,051–7,064
Winant CD (2008) Three-dimensional residual tidal circulation in an elongated, rotating basin. J Phys Oceanogr 38:1278–1295
Wong K, Valle-Levinson A (2002) On the relative importance of the remote and local wind effects on the subtidal exchange at the entrance to the Chesapeake Bay. J Mar Res 60:477–498
Acknowledgments
Current data from moorings deployed in 2006 at Reloncavi Fjord were obtained under project CONA-C12F 06–02 supported by National Oceanographic Committee of Chile. A.VL acknowledges support from NSF project 0825876 and a Fellowship under Program of Short Stays 801100008 supported by CONICYT (Chile), to analyze some of the data at Universidad de Valparaiso. A.VL also acknowledges support from the Fulbright Commission and CSIC, Spain, which allowed completion of this document. Comments from two anonymous reviewers helped clarify several aspects of this presentation.
Author information
Authors and Affiliations
Corresponding author
Additional information
Responsible Editor: Rockwell Geyer
This article is part of the Topical Collection on Physics of Estuaries and Coastal Seas 2012
Rights and permissions
About this article
Cite this article
Valle-Levinson, A., Caceres, M.A. & Pizarro, O. Variations of tidally driven three-layer residual circulation in fjords. Ocean Dynamics 64, 459–469 (2014). https://doi.org/10.1007/s10236-014-0694-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10236-014-0694-9