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On Gulf Stream meander characteristics near Cape Hatteras
OLR (1986) 33 (12)
A. Physical Oceanography
991
with the combined inversion. Our conclusion is that the inversion of the combined data sets produces results much improved over those from using either acoustic or hydrographic/chemical constraints in isolation. WHOI, Woods Hole, MA 02543, USA.
86:6764 McWiiliams, J.C. and P.R. Gent, 1986. The evolution of sub-mesoscale, coherent vortices on the r plane. Geophys. astrophys. Fluid Dynam., 35(3): 235-255. NCAR, Boulder, CO 80307, USA.
86:6761 Kosro, P.M. and Adriana Huyer, 1986. CTD and velocity surveys of seaward jets off northern California, July 1981 and 1982. J. geophys. Res., 91(C6):7680-7690.
86:6765 Miyaji, Kuniaki and Naofumi Inoue, 1986. Characteristics of the flow of the Kuroshio in northwest waters off Amami Oshima in the East China Sea. Bull. Seikai reg. Fish. Res. Lab., 63:1-14. (In Japanese, English abstract.)
Two mesoscale surveys, conducted near Point Arena, California, to determine the structure and circulation associated with tongues of cold surface water, showed that the cold water tongues were the surface manifestation of hydrographic and current anomalies that extended to a depth of at least 100 m. In each case, strong seaward flow was observed along the northern edge of the cold tongue, which also marked a shallow water mass boundary between low-salinity surface waters to the north and highsalinity waters to the south. The seaward jets were very strong and narrow, with strong shears; they were largely geostrophic, had transports exceeding 1.5 sverdrups, and can persist for 2-3 weeks. There is evidence that the seaward jets are recurrent features in the vicinity of Point Arena. Coll. of Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA. 86:6762 Lie, Heung-Jae and Sang-Kyung Byun, 1985. Summertime southward current along the east coast of Korea. J. oceanol. Soc. Korea, 20(2):22-27. Hydrographic results showed that isotherms, isohalines and isopycnals had a downward slope toward the coast in a layer of 0-100 m and large horizontal gradients across the shelf of salinity and density, mainly due to heavy precipitation in summer. A strong southward flow along the coast reaching maximal speed of ~ 7 0 cm/sec in the nearshore area was observed; its shear and speed were on the order of those of geostrophic currents. KORDI, P.O. Box 17, Yeong-Dong, Seoul 135, Korea. 86:6763 Maksimenko, N.A., 1986. Transport and mixing of ocean water in synoptic eddy fields according to POLYMODE data. Okeanologiia, 26(2): 191-198. (In Russian, English abstract.) Transport processes were studied and an equation of passive tracer transport in the eddy field was solved. Results indicated strong mixing in the POLYMODE region characteristic of quasi two-dimensional geostrophic turbulence.
At the time and location of this study (December '82 to February '83) the Kuroshio stream 'is rather stagnant.' Water properties and their fluctuations are described. Seikai Reg. Fish. Res. Lab., Kokubumachi, Nagasaki 850, Japan. (fcs) 86:6766 Ou, H.W. and A.L. Gordon, 1986. Spin-down of baroclinic eddies under sea ice. J. geophys. Res., 91(C6):7623-7630. For anticyclonic eddies the ice stress, besides directly spinning down the azimuthal flow within the mixed layer, generates an Ekman divergence that raises the pycnocline near the eddy axis. For eddies of the size of the baroclinic radius of deformation, the doming reaches a quasi-stationary state on the frictional time scale T, which generally is of the order of days. Upward entrainment of the fluid across the pycnocline causes a flow convergence below the mixed layer that continues to spin down the deeper flow and flatten the dome. The erosion of the dome, however, occurs over a much longer time scale, of the order of a year or longer. The pycnocline dome observed over the Antarctic warm cells is thus likely to survive into the following freezing season and provide a preconditioning for the deep convection in the Weddell Sea. LamontDoherty Geol. Observ., Palisades, NY 10964, USA. 86:6767 Samolyubov, B.I., 1986. Studies and appfication of self-similar properties of a near-bottom stratified flow. Meteorologiya Gidrol., 1:83-93. (In Russian, English abstract.) 86:6768 Tracey, K.L. and D.R. Watts, 1986. On Gulf Stream meander characteristics near Cape Hatteras. J. geophys. Res., 91(C6):7587-7602. Monitoring studies (1979-82) showed that near Cape Hatteras, the Gulf Stream was present over half of the time within a narrow 10-kin range. The distributions became progressively more symmetric and
992
A. Physical Oceanography
the ranges widened downstream such that in the eastern portion of the study area the Gulf Stream could be found with equal probability throughout its 145-km excursion range. Downstream propagation rates increase smoothly from about 14 km/d for meanders with periods and wavelengths (33 days, 460 km) to over 45 km/d for the (4 days, 180 km) meanders. Meander amplitudes show rapid growth rates in two separate bands, near (4-5 days, 180-230 km) and (10-33 days, 300-500 km). Grad. Sch. of Oceanogr., Univ. of Rhode Island, Narragansett, RI 02882, USA. 86:6769 Verron, Jacques, 1986. Topographic eddies in temporally varying oceanic flows, Geophys. astrophys. Fluid Dynam., 35(3):257-276. In certain cases, vortex shedding is observed in the lee of obstacles. Such shedding can be explained as the consequence of both an enhanced process of vorticity dissipation over the topography which locally affects the balance of potential vorticity on the advective timescale, and a periodic dominance of advective effects which sweep the fluid particles trapped on the seamount. For refined resolution and smallest viscosity the model will predict flows in which the shed eddies are coherent structures with closed streamlines. The model suggests a mechanism by which topographically generated eddies may be swept away from a seamount in the ocean. Inst. de Mecan. de Grenoble, BP 68, 38402 St Martin D'Heres Cedex, France.
A l l 0 . Water masses and fronts 86:6770 Balopoulos, E.Th., 1985. An analysis of the coastal water masses in the northwestern Aegean Sea. Thalassographica, 8:7-17. Analysis of temperature and salinity distributions reveals three major factors influencing water mass characteristics, circulation and mixing: river flow, the intrusion of high salinity Aegean Sea water, and air-sea interaction processes (autumn cooling and wind). Natl. Centre for Mar. Res., GR-166 04 Hellinikon, Greece.
A120. Convergences, divergences, upwelling 86:6771 Voytov, V.I. and V.M. Zhurbas, 1986. On synoptic variability of surface temperature and salinity
OLR (1986) 33 (12)
fields in the Canary Upwelling. Okeanologiia, 26(2):186-190. (In Russian, English abstract.) Surface temperature and CTD data for the area (21°07"N-22°20"N) indicate (1) a high negative correlation exists between surface temperature and salinity during upwelling events, although the opposite occurs when conditions unfavorable for upwelling prevail; (2) at the boundary between upwelled and open ocean water, the horizontal temperature gradient across the thermohaline front was as much as 0.7C°; and (3) upwelled waters originated from 10(O200 m depths. (slr)
A150. Tides and sea level 86:6772 Fang, Guohong, 1985. A finite difference-least squares technique for solving tidal wave equations with specific application to the modeling of M 2 tide in the Huanghai Sea. Scientia sin., (B)28(10):1110-1120. Inst. of Oceanol., Acad. Sin., Qingdao, People's Republic of China.
A160. Waves, oscillations 86:6773 Brink, K.H., 1986. Scattering of long coastal-trapped waves due to bottom irregularities. Dynam. Atmos. Oceans, 10(2): 149-164. The topographic scattering of long coastal-trapped waves is considered to see whether or not stratification tends to weaken scattering. Numerical examples show that this is not the case in general. Rather, susceptibility to scattering depends upon the particular example; in some cases it weakens with stratification, and in others it strengthens. WHOI, Woods Hole, MA 02543, USA. 86:6774 Clancy, R.M., J.E. Kaitala and L.F. Zambresky, 1986. The Fleet Numerical Oceanography Center Global Spectral Ocean Wave Model. Bull. Am. met. Soc., 67(5):498-512. The Spectral Ocean Wave Model (SOWM) has been operational since the mid 1970s; the Global Spectral Ocean Wave Model (GSOWM) was developed to replace it. An operational test of GSOWM (winter, 1984/85) using buoy, ocean-weather-station, and ship-reported wave-height data for verification, indicated that it was superior to SOWM and that both models exhibited root-mean-square significant-wave-height errors on the order of 1 m.
A. Physical Oceanography
991
with the combined inversion. Our conclusion is that the inversion of the combined data sets produces results much improved over those from using either acoustic or hydrographic/chemical constraints in isolation. WHOI, Woods Hole, MA 02543, USA.
86:6764 McWiiliams, J.C. and P.R. Gent, 1986. The evolution of sub-mesoscale, coherent vortices on the r plane. Geophys. astrophys. Fluid Dynam., 35(3): 235-255. NCAR, Boulder, CO 80307, USA.
86:6761 Kosro, P.M. and Adriana Huyer, 1986. CTD and velocity surveys of seaward jets off northern California, July 1981 and 1982. J. geophys. Res., 91(C6):7680-7690.
86:6765 Miyaji, Kuniaki and Naofumi Inoue, 1986. Characteristics of the flow of the Kuroshio in northwest waters off Amami Oshima in the East China Sea. Bull. Seikai reg. Fish. Res. Lab., 63:1-14. (In Japanese, English abstract.)
Two mesoscale surveys, conducted near Point Arena, California, to determine the structure and circulation associated with tongues of cold surface water, showed that the cold water tongues were the surface manifestation of hydrographic and current anomalies that extended to a depth of at least 100 m. In each case, strong seaward flow was observed along the northern edge of the cold tongue, which also marked a shallow water mass boundary between low-salinity surface waters to the north and highsalinity waters to the south. The seaward jets were very strong and narrow, with strong shears; they were largely geostrophic, had transports exceeding 1.5 sverdrups, and can persist for 2-3 weeks. There is evidence that the seaward jets are recurrent features in the vicinity of Point Arena. Coll. of Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA. 86:6762 Lie, Heung-Jae and Sang-Kyung Byun, 1985. Summertime southward current along the east coast of Korea. J. oceanol. Soc. Korea, 20(2):22-27. Hydrographic results showed that isotherms, isohalines and isopycnals had a downward slope toward the coast in a layer of 0-100 m and large horizontal gradients across the shelf of salinity and density, mainly due to heavy precipitation in summer. A strong southward flow along the coast reaching maximal speed of ~ 7 0 cm/sec in the nearshore area was observed; its shear and speed were on the order of those of geostrophic currents. KORDI, P.O. Box 17, Yeong-Dong, Seoul 135, Korea. 86:6763 Maksimenko, N.A., 1986. Transport and mixing of ocean water in synoptic eddy fields according to POLYMODE data. Okeanologiia, 26(2): 191-198. (In Russian, English abstract.) Transport processes were studied and an equation of passive tracer transport in the eddy field was solved. Results indicated strong mixing in the POLYMODE region characteristic of quasi two-dimensional geostrophic turbulence.
At the time and location of this study (December '82 to February '83) the Kuroshio stream 'is rather stagnant.' Water properties and their fluctuations are described. Seikai Reg. Fish. Res. Lab., Kokubumachi, Nagasaki 850, Japan. (fcs) 86:6766 Ou, H.W. and A.L. Gordon, 1986. Spin-down of baroclinic eddies under sea ice. J. geophys. Res., 91(C6):7623-7630. For anticyclonic eddies the ice stress, besides directly spinning down the azimuthal flow within the mixed layer, generates an Ekman divergence that raises the pycnocline near the eddy axis. For eddies of the size of the baroclinic radius of deformation, the doming reaches a quasi-stationary state on the frictional time scale T, which generally is of the order of days. Upward entrainment of the fluid across the pycnocline causes a flow convergence below the mixed layer that continues to spin down the deeper flow and flatten the dome. The erosion of the dome, however, occurs over a much longer time scale, of the order of a year or longer. The pycnocline dome observed over the Antarctic warm cells is thus likely to survive into the following freezing season and provide a preconditioning for the deep convection in the Weddell Sea. LamontDoherty Geol. Observ., Palisades, NY 10964, USA. 86:6767 Samolyubov, B.I., 1986. Studies and appfication of self-similar properties of a near-bottom stratified flow. Meteorologiya Gidrol., 1:83-93. (In Russian, English abstract.) 86:6768 Tracey, K.L. and D.R. Watts, 1986. On Gulf Stream meander characteristics near Cape Hatteras. J. geophys. Res., 91(C6):7587-7602. Monitoring studies (1979-82) showed that near Cape Hatteras, the Gulf Stream was present over half of the time within a narrow 10-kin range. The distributions became progressively more symmetric and
992
A. Physical Oceanography
the ranges widened downstream such that in the eastern portion of the study area the Gulf Stream could be found with equal probability throughout its 145-km excursion range. Downstream propagation rates increase smoothly from about 14 km/d for meanders with periods and wavelengths (33 days, 460 km) to over 45 km/d for the (4 days, 180 km) meanders. Meander amplitudes show rapid growth rates in two separate bands, near (4-5 days, 180-230 km) and (10-33 days, 300-500 km). Grad. Sch. of Oceanogr., Univ. of Rhode Island, Narragansett, RI 02882, USA. 86:6769 Verron, Jacques, 1986. Topographic eddies in temporally varying oceanic flows, Geophys. astrophys. Fluid Dynam., 35(3):257-276. In certain cases, vortex shedding is observed in the lee of obstacles. Such shedding can be explained as the consequence of both an enhanced process of vorticity dissipation over the topography which locally affects the balance of potential vorticity on the advective timescale, and a periodic dominance of advective effects which sweep the fluid particles trapped on the seamount. For refined resolution and smallest viscosity the model will predict flows in which the shed eddies are coherent structures with closed streamlines. The model suggests a mechanism by which topographically generated eddies may be swept away from a seamount in the ocean. Inst. de Mecan. de Grenoble, BP 68, 38402 St Martin D'Heres Cedex, France.
A l l 0 . Water masses and fronts 86:6770 Balopoulos, E.Th., 1985. An analysis of the coastal water masses in the northwestern Aegean Sea. Thalassographica, 8:7-17. Analysis of temperature and salinity distributions reveals three major factors influencing water mass characteristics, circulation and mixing: river flow, the intrusion of high salinity Aegean Sea water, and air-sea interaction processes (autumn cooling and wind). Natl. Centre for Mar. Res., GR-166 04 Hellinikon, Greece.
A120. Convergences, divergences, upwelling 86:6771 Voytov, V.I. and V.M. Zhurbas, 1986. On synoptic variability of surface temperature and salinity
OLR (1986) 33 (12)
fields in the Canary Upwelling. Okeanologiia, 26(2):186-190. (In Russian, English abstract.) Surface temperature and CTD data for the area (21°07"N-22°20"N) indicate (1) a high negative correlation exists between surface temperature and salinity during upwelling events, although the opposite occurs when conditions unfavorable for upwelling prevail; (2) at the boundary between upwelled and open ocean water, the horizontal temperature gradient across the thermohaline front was as much as 0.7C°; and (3) upwelled waters originated from 10(O200 m depths. (slr)
A150. Tides and sea level 86:6772 Fang, Guohong, 1985. A finite difference-least squares technique for solving tidal wave equations with specific application to the modeling of M 2 tide in the Huanghai Sea. Scientia sin., (B)28(10):1110-1120. Inst. of Oceanol., Acad. Sin., Qingdao, People's Republic of China.
A160. Waves, oscillations 86:6773 Brink, K.H., 1986. Scattering of long coastal-trapped waves due to bottom irregularities. Dynam. Atmos. Oceans, 10(2): 149-164. The topographic scattering of long coastal-trapped waves is considered to see whether or not stratification tends to weaken scattering. Numerical examples show that this is not the case in general. Rather, susceptibility to scattering depends upon the particular example; in some cases it weakens with stratification, and in others it strengthens. WHOI, Woods Hole, MA 02543, USA. 86:6774 Clancy, R.M., J.E. Kaitala and L.F. Zambresky, 1986. The Fleet Numerical Oceanography Center Global Spectral Ocean Wave Model. Bull. Am. met. Soc., 67(5):498-512. The Spectral Ocean Wave Model (SOWM) has been operational since the mid 1970s; the Global Spectral Ocean Wave Model (GSOWM) was developed to replace it. An operational test of GSOWM (winter, 1984/85) using buoy, ocean-weather-station, and ship-reported wave-height data for verification, indicated that it was superior to SOWM and that both models exhibited root-mean-square significant-wave-height errors on the order of 1 m.