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Circulation of waters in the northern Indian Ocean during the winter monsoon (In Russian; English abstract)
260
Oceanographic Abstracts
NIGAM,S. D. and P. D. NIGAM, 1962. Wave propagation ih rotating liquids. Proc. Roy. Soe.,
London, Ser. A., 266 (1325): 247-256.
The directional distribution and attenuation of waves from a local source of fixed frequency ¢o placed at the axis of an incompressible, inviscid, unbounded liquid rotating as a solid body with a constant angular velocity 12 and having a uniform velocity of translation U have been studied. Following the technique developed by Lighthill it is found that when 4.Q2 < oJ2, the waves are propagated downstream only and they are confined in certain regions and when 4.Q2 ~-oJ2 the waves travel downstream as well as upstream. There exists a region upstream in which the waves do not penetrate. The cases of sources of finite or infinitesimal duration are also discussed briefly. OVCHINNIKOV, I. M., 1961. Circulation of waters in the northern Indian Ocean during the winter monsoon (in Russian; English abstract). Okeanolog. lssledov., Mezhd. Komitet Proved. Mezhd. Geofiz. Goda, Prezidiume Akad. Nauk, SSSR, (4): 18-24. The paper is based on data of direct observations of currents during the 31st cruise of the R/V Vityaz. Seventeen dam-buoy stations were occupied and at 140 stations observations were carried out with the differential method. The maps of currents are given for level of 15, 200 and 500 m (preliminary), and 1000 m, the latter only according to the data of the dam-buoy stations. It has been determined that at the depth of 1000 m the currents with 10-20 cm/sec velocity to the north of the frontal zone are generally directed to the east, and to the south of the frontal zone--to the west. Contrary to previous observations on a large part of the aquator to the north of the frontal zone the current even on the 100-200 m level is directed generally to the east, i.e. against the current on the surface. The data is given of observations along the two profiles (76 ° and 90 ° E) of the vertical structure of currents, their latitudinal distribution and meridional components.
PASTERNAK,F. A., 1961. New data on the spzcific composition and distribution of the deep-sea pennatularian genus Kophobelemnon. Trud. Inst. Okean., Akad. Nauk SSSR, 45: 240-258. The collection of deep-sea Pennatularia (fam. Kophobelemnaidae) from Northern Pacific was examined. The results of this work gave the opportunity to include the genus Sclerobelemnon into the genus Kophobelemnon, divided into two subgenera--Eukophobelemnon and Sclerobelemnon.
PHLEGER,F. B. and G. C. EWING, 1962. Sedimentology and oceanography of coastal lagoons in Baja California, Mexico. Bull. Geol. Soc.,Amer., 73 (2): 145-182. The arid Ojo de Liebre area, Baja California, Mexico, has three coastal lagoons. The hypersaline Laguna Ojo de Liebre has brine pans separated from the inner lagoon by a low barrier breached by small channels and extensive salt flats. The lagoon barrier, approximately 2 miles wide, has numerous high barchan dunes. The lagoon has relatively deep, steep-walled channels and wide intertidal flats; the main channels are directly behind the' lagoon barrier. Spartina and Salicornia marsh grown on the inner edges of the intertidal flats and on land bridges between lagoons. Maximum tidal currents are at least 2.5 knots in the inlets and lower channels and are very turbulent. Tidal delay between the inlet and the inner lagoon is approximately 3 hr. Tidal ranges are 4-9 ft. Most sediment is fine to very fine well-sorted and slightly skewed sand. The immediate source of the sand is the lagoon barrier, open ocean beach, and near-shore zone. Less well-sorted sand and pebbles in some channels are attributed to former river deposition. Silt and clay in the inner lagoon and marshes are in part derived from older sediment. The average sand is approximately 95 per cent quartz, 4 per cent dark minerals, and 1 per cent or less Foraminifera and shell. Most samples contain apatite pellets presumed to be authigenic in the near-shore open ocean. The following foraminiferal assemblages have been differentiated: near-shore open-ocean, dune, lower-lagoon, inner-lagoon, and marsh. Three molluscan assemblages are recognized. Organic production in the lagoon is very high; average fixation is 47.2 mgC/m3/day. There are large living populations of Foraminifera and Mollusca. Processes of sedimentation include wind delivery of sand from the barrier and distribution by turbulent tidal currents. Most deposition occurs on inter-tidal flats and in the inner lagoon, due to loss of water turbulence. The channels next to the barrier tend to maintain themselves. Tidal delay is related to the mean depth of the lagoon, roughness of the bottom, and width of the channel. The Ojo de Liebre barrier is believed to have begun as a fringing beach on a gently sloping coastal plain when sea level was about 40 ft lower than at present. The inlets developed as a result of hydraulic head due to tidal delay. A river supplizd abundant sand, and the barrier grew upward as sea level rose. The barrier has prograded seaward about 1 mile in the last 1800 ± 200 years. Land bridges developed and separated the lagoon into three lagoons owing to meeting of tidal currents which were introduced simultaneously through adjacent inlets and which result in reduced current and rapid sediment deposition. This process is observed in Laguna Santo Domingo. Evidence is given for an earlier lagoon cycle, older than 30,000 year~ R. P.
Oceanographic Abstracts
NIGAM,S. D. and P. D. NIGAM, 1962. Wave propagation ih rotating liquids. Proc. Roy. Soe.,
London, Ser. A., 266 (1325): 247-256.
The directional distribution and attenuation of waves from a local source of fixed frequency ¢o placed at the axis of an incompressible, inviscid, unbounded liquid rotating as a solid body with a constant angular velocity 12 and having a uniform velocity of translation U have been studied. Following the technique developed by Lighthill it is found that when 4.Q2 < oJ2, the waves are propagated downstream only and they are confined in certain regions and when 4.Q2 ~-oJ2 the waves travel downstream as well as upstream. There exists a region upstream in which the waves do not penetrate. The cases of sources of finite or infinitesimal duration are also discussed briefly. OVCHINNIKOV, I. M., 1961. Circulation of waters in the northern Indian Ocean during the winter monsoon (in Russian; English abstract). Okeanolog. lssledov., Mezhd. Komitet Proved. Mezhd. Geofiz. Goda, Prezidiume Akad. Nauk, SSSR, (4): 18-24. The paper is based on data of direct observations of currents during the 31st cruise of the R/V Vityaz. Seventeen dam-buoy stations were occupied and at 140 stations observations were carried out with the differential method. The maps of currents are given for level of 15, 200 and 500 m (preliminary), and 1000 m, the latter only according to the data of the dam-buoy stations. It has been determined that at the depth of 1000 m the currents with 10-20 cm/sec velocity to the north of the frontal zone are generally directed to the east, and to the south of the frontal zone--to the west. Contrary to previous observations on a large part of the aquator to the north of the frontal zone the current even on the 100-200 m level is directed generally to the east, i.e. against the current on the surface. The data is given of observations along the two profiles (76 ° and 90 ° E) of the vertical structure of currents, their latitudinal distribution and meridional components.
PASTERNAK,F. A., 1961. New data on the spzcific composition and distribution of the deep-sea pennatularian genus Kophobelemnon. Trud. Inst. Okean., Akad. Nauk SSSR, 45: 240-258. The collection of deep-sea Pennatularia (fam. Kophobelemnaidae) from Northern Pacific was examined. The results of this work gave the opportunity to include the genus Sclerobelemnon into the genus Kophobelemnon, divided into two subgenera--Eukophobelemnon and Sclerobelemnon.
PHLEGER,F. B. and G. C. EWING, 1962. Sedimentology and oceanography of coastal lagoons in Baja California, Mexico. Bull. Geol. Soc.,Amer., 73 (2): 145-182. The arid Ojo de Liebre area, Baja California, Mexico, has three coastal lagoons. The hypersaline Laguna Ojo de Liebre has brine pans separated from the inner lagoon by a low barrier breached by small channels and extensive salt flats. The lagoon barrier, approximately 2 miles wide, has numerous high barchan dunes. The lagoon has relatively deep, steep-walled channels and wide intertidal flats; the main channels are directly behind the' lagoon barrier. Spartina and Salicornia marsh grown on the inner edges of the intertidal flats and on land bridges between lagoons. Maximum tidal currents are at least 2.5 knots in the inlets and lower channels and are very turbulent. Tidal delay between the inlet and the inner lagoon is approximately 3 hr. Tidal ranges are 4-9 ft. Most sediment is fine to very fine well-sorted and slightly skewed sand. The immediate source of the sand is the lagoon barrier, open ocean beach, and near-shore zone. Less well-sorted sand and pebbles in some channels are attributed to former river deposition. Silt and clay in the inner lagoon and marshes are in part derived from older sediment. The average sand is approximately 95 per cent quartz, 4 per cent dark minerals, and 1 per cent or less Foraminifera and shell. Most samples contain apatite pellets presumed to be authigenic in the near-shore open ocean. The following foraminiferal assemblages have been differentiated: near-shore open-ocean, dune, lower-lagoon, inner-lagoon, and marsh. Three molluscan assemblages are recognized. Organic production in the lagoon is very high; average fixation is 47.2 mgC/m3/day. There are large living populations of Foraminifera and Mollusca. Processes of sedimentation include wind delivery of sand from the barrier and distribution by turbulent tidal currents. Most deposition occurs on inter-tidal flats and in the inner lagoon, due to loss of water turbulence. The channels next to the barrier tend to maintain themselves. Tidal delay is related to the mean depth of the lagoon, roughness of the bottom, and width of the channel. The Ojo de Liebre barrier is believed to have begun as a fringing beach on a gently sloping coastal plain when sea level was about 40 ft lower than at present. The inlets developed as a result of hydraulic head due to tidal delay. A river supplizd abundant sand, and the barrier grew upward as sea level rose. The barrier has prograded seaward about 1 mile in the last 1800 ± 200 years. Land bridges developed and separated the lagoon into three lagoons owing to meeting of tidal currents which were introduced simultaneously through adjacent inlets and which result in reduced current and rapid sediment deposition. This process is observed in Laguna Santo Domingo. Evidence is given for an earlier lagoon cycle, older than 30,000 year~ R. P.