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87:6024 Stratification and circulation at the Agulhas Retroflection
OI~R (1987) 34 ( 11)
A. Physical Oceanography
ASO. Circulation 87:6022 Eriksen, C.C. and E.J. Katz, 1987. Equatorial dynamics. [Review.] Revs Geophys., 25(2):217226. Substantial progress has been made in equatorial ocean dynamics in the last four years, largely as a result of several multi-institution programs. Results of these programs were summarized at the August 1986 U.S. TOGA (Tropical Ocean Global Atmosphere) workshop held in Hawaii; this review draws heavily from those presentations. Discussion is restricted to dynamical aspects of equatorial ocean circulation, both steady and time-dependent. Sections review vertical and horizontal mixing, instabilities of zonal currents, wave propagation, climatology, western boundary phenomena, and largescale adjustment. School of Oceanogr., Univ. of Washington, Seattle, WA, USA. 87:6023 Galerkin, G.L., A.S. Monin and S.V. Sergunin, 1987. Seasonal sources of thermohafine circulation in the North Atlantic. Dokl. Earth Sci. Sect. (a translation of Dokl. Akad. Nauk SSSR), 282(16):211-213. Estimates of the factors affecting surface water density, viz. cooling and salinification, are developed. These processes have been estimated previously only as yearly averages rather than seasonally. Shirshov Inst. of Oceanol., Acad. of Sci., Moscow, USSR. Orb) 87:6024 Gordon, A.L., J.R.E. Lutjeharms and M.L. Grtlndlingh, 1987. Stratification and circulation at the Agullms Retroflection. Deep-Sea Res., 34(4A): 565-599. Study results show that (1) within the upper 1500 m, the Agulhas Current introduces about 70 Sv of water into the Agulhas Retroflection; a small part of this flow combines with 5 Sv of South Atlantic Water to flow into the South Atlantic. Most of the transport returns to the Indian Ocean as the current undergoes a sharp retroflection along 21°E. (2) To the west of the Agulhas Retroflection are two warm-core eddies formed from the Agulhas Current. (3) The Agulhas Current introduces several Indian Ocean Water types into the Retroflection region. (4) Within the Retroflection, Indian Ocean water masses are modified: upper thermocline water upon exposure to the colder atmosphere forms anomalously salty water; and deeper thermocline water mixes with South Atlantic Water which enters the Retroflection region
91.5
via anticyclonic circulation of the warm-core eddies. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. 87:6025 Latif, Mojib, 1987. Tropical ocean circulation experiments. J. phys. Oeeanogr., 17(2):246-263. A primitive equation model of the equatorial Pacific was forced by realistic wind stress distributions over decades. In the first experiment the model was forced by an objectively analyzed wind field; in the second, a subjectively analyzed wind field was used. Results indicate a strong sensitivity of the model to the choice of wind field. Model results in the eastern Pacific show big differences between the two model runs. In the second model run, sea level, temperature and zonal currents show pronounced interannual variations within the equatorial belt from 10°N to 10°S. The model reproduces most of the basic features observed during the 1982/83 E1 Niflo event: deceleration of the equatorial undercurrent, evolution of eastward surface currents and zonal redistribution of heat associated with an eastward propagation of warm water. Max Planck Inst. fur Meteorol., D 2000 Hamburg 13, FRG. 87:6026 Piola, A.R., H.A. Figueroa and A.A. Bianchi, 1987. Some aspects of the surface circulation south of 20°S revealed by First GARP Global Experiment drifters. J. geophys. Res., 92(C5):5101-5114. Daily averaged positions from about 280 satellitetracked drifting buoys are used to estimate the sea surface current velocity field south of 20°S. The time-averaged surface velocity field based on velocity averages over 4 ° x 4 ° areas is used to construct the surface stream function. Gross features of the mean circulation are generally in agreement with other representations of time-averaged circulation, although they do differ in details from the climatological relative surface dynamic topographies in the southern hemisphere subtropical gyres. Mean and eddy horizontal momentum fluxes based on a 2 ° × 2 ° grid are estimated for the region south of 40°S. The zonally averaged momentum flux at the sea surface for the region of the Antarctic Circumpolar Current, from 40 ° to 60°S, leads to a momentum flux divergence of 60 cm 2 s 2 indicating a meridional flux of eastward momentum away from the current axis, but the sign of the flux divergence remains uncertain. Dept. Oceanogr., Servicio de Hidrografia Naval, Buenos Aires, Argentina. 87:6027 Price, J.F., E.A. Terray and R.A. Weller, 1987. Upper ocean dynamics. [Review.] Revs Geophys., 25(2): 193-203.
A. Physical Oceanography
ASO. Circulation 87:6022 Eriksen, C.C. and E.J. Katz, 1987. Equatorial dynamics. [Review.] Revs Geophys., 25(2):217226. Substantial progress has been made in equatorial ocean dynamics in the last four years, largely as a result of several multi-institution programs. Results of these programs were summarized at the August 1986 U.S. TOGA (Tropical Ocean Global Atmosphere) workshop held in Hawaii; this review draws heavily from those presentations. Discussion is restricted to dynamical aspects of equatorial ocean circulation, both steady and time-dependent. Sections review vertical and horizontal mixing, instabilities of zonal currents, wave propagation, climatology, western boundary phenomena, and largescale adjustment. School of Oceanogr., Univ. of Washington, Seattle, WA, USA. 87:6023 Galerkin, G.L., A.S. Monin and S.V. Sergunin, 1987. Seasonal sources of thermohafine circulation in the North Atlantic. Dokl. Earth Sci. Sect. (a translation of Dokl. Akad. Nauk SSSR), 282(16):211-213. Estimates of the factors affecting surface water density, viz. cooling and salinification, are developed. These processes have been estimated previously only as yearly averages rather than seasonally. Shirshov Inst. of Oceanol., Acad. of Sci., Moscow, USSR. Orb) 87:6024 Gordon, A.L., J.R.E. Lutjeharms and M.L. Grtlndlingh, 1987. Stratification and circulation at the Agullms Retroflection. Deep-Sea Res., 34(4A): 565-599. Study results show that (1) within the upper 1500 m, the Agulhas Current introduces about 70 Sv of water into the Agulhas Retroflection; a small part of this flow combines with 5 Sv of South Atlantic Water to flow into the South Atlantic. Most of the transport returns to the Indian Ocean as the current undergoes a sharp retroflection along 21°E. (2) To the west of the Agulhas Retroflection are two warm-core eddies formed from the Agulhas Current. (3) The Agulhas Current introduces several Indian Ocean Water types into the Retroflection region. (4) Within the Retroflection, Indian Ocean water masses are modified: upper thermocline water upon exposure to the colder atmosphere forms anomalously salty water; and deeper thermocline water mixes with South Atlantic Water which enters the Retroflection region
91.5
via anticyclonic circulation of the warm-core eddies. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. 87:6025 Latif, Mojib, 1987. Tropical ocean circulation experiments. J. phys. Oeeanogr., 17(2):246-263. A primitive equation model of the equatorial Pacific was forced by realistic wind stress distributions over decades. In the first experiment the model was forced by an objectively analyzed wind field; in the second, a subjectively analyzed wind field was used. Results indicate a strong sensitivity of the model to the choice of wind field. Model results in the eastern Pacific show big differences between the two model runs. In the second model run, sea level, temperature and zonal currents show pronounced interannual variations within the equatorial belt from 10°N to 10°S. The model reproduces most of the basic features observed during the 1982/83 E1 Niflo event: deceleration of the equatorial undercurrent, evolution of eastward surface currents and zonal redistribution of heat associated with an eastward propagation of warm water. Max Planck Inst. fur Meteorol., D 2000 Hamburg 13, FRG. 87:6026 Piola, A.R., H.A. Figueroa and A.A. Bianchi, 1987. Some aspects of the surface circulation south of 20°S revealed by First GARP Global Experiment drifters. J. geophys. Res., 92(C5):5101-5114. Daily averaged positions from about 280 satellitetracked drifting buoys are used to estimate the sea surface current velocity field south of 20°S. The time-averaged surface velocity field based on velocity averages over 4 ° x 4 ° areas is used to construct the surface stream function. Gross features of the mean circulation are generally in agreement with other representations of time-averaged circulation, although they do differ in details from the climatological relative surface dynamic topographies in the southern hemisphere subtropical gyres. Mean and eddy horizontal momentum fluxes based on a 2 ° × 2 ° grid are estimated for the region south of 40°S. The zonally averaged momentum flux at the sea surface for the region of the Antarctic Circumpolar Current, from 40 ° to 60°S, leads to a momentum flux divergence of 60 cm 2 s 2 indicating a meridional flux of eastward momentum away from the current axis, but the sign of the flux divergence remains uncertain. Dept. Oceanogr., Servicio de Hidrografia Naval, Buenos Aires, Argentina. 87:6027 Price, J.F., E.A. Terray and R.A. Weller, 1987. Upper ocean dynamics. [Review.] Revs Geophys., 25(2): 193-203.