360 likes | 557 Views
Russian Academy of Sciences. Physical Oceanography at SIO RAS, and Selected Results on the South Atlantic Peter O. Zavialov Deputy Director, Shirshov Institute of Oceanology Head, Physical Oceanography Division.
E N D
Russian Academy of Sciences Physical Oceanography at SIO RAS,andSelected Results on the South Atlantic Peter O. ZavialovDeputy Director, Shirshov Institute of Oceanology Head, Physical Oceanography Division Talk presented at SAMOC-3 Meeting, Rio de Janeiro, Brazil, May 11, 2010
Founded: 1946 Employees: ~1200 Scientists: ~600 PhD’s: ~160 DSc’s: ~90 Graduate students: ~60 Fleet: 6 P.P.SHIRSHOV INSTITUTE OF OCEANOLOGY (SIO RAS) Biological OceanographyDivision Geological Oceanography Division Physical Oceanography Division Ocean Engineering Division 13 Labs 13 Labs 7 Labs 6 Labs + 5 regional filial branches
SIO RAS PO Division in 2009 Faculty and staff :108scientists, 53engineers, total161 Graduate students: 17 Publications in 2009: 109journal aricles, 6books
1. Antarctic Bottom Water transportthrough SA abyssal channels [E.G.Morozov et al.] – multiple publications, 2000-2010
Vema Channelis a deep passage (4700 m) for AABW in the Rio Grande Rise (4200 m deep plateau) The transport of AABW in the Vema Channel is estimated at 3 Sv. Mean velocities are 30 cm/s; Maximum velocities reach 60 cm/s
Potential temperature across the Vema Channel The flow is strongly mixed. The coldest water is displaced to the eastern wall of the channel due to the Ekman friction
Meridional velocity in Vema ChannelNote the southward countercurrent above 4100 m
Velocity profile in Chain F.Z.Total transport through the Chain F.Z. is estimated as 0.1 Sv“Bifurcation” of the flow while sinking from 4000 mto 4500 m.Agreement with laboratory model experiment.
2. CURRENTS AND WATER MASSES IN THE SOUTH ATLANTIC • Golivetz S.V., and M.N. Koshlyakov, Cyclonic Eddies of the Subantarctic Front and Formation of the Antarctic Intermediate Water. Oceanology 43, 305–317. 2003. • Golivetz S.V., and M.N. Koshlyakov, Eddy Formation at the Subantarcic Front from Sattellite Observations and Formation of the Antarctic Intermediate Water. Oceanology 44, 451–460. 2004. • Golivetz S.V., and M.N. Koshlyakov, Synoptic Eddies of the Subantarctic and Agulhas Fronts and Generation of the Antarctic Intermediate Water. Oceanology 49, 151–165. • Gladyshev S.V., M.N. Koshlyakov, and R.Yu. Tarakanov, Currents in the Drake Passage Based on Observations in 2007. Oceanology 48, 821–833, 2008. • Koshlyakov M.N., S.V. Gladyshev, R.Yu. Tarakanov, and N.I. Ryzhikov, Deep Currents in the Central Part of Drake Passage based on the Data of 2008 Hydrographic Survey. Oceanology, 2010 (in press). •Tarakanov R. Yu., Circumpolar Bottom Water in the Scotia Sea and the Drake Passage, Oceanology 50 (1), 1–1, 2010. M.V. Koshlyakov
Abyssal and deep water masses at section Drk03 1) 11-15/12/2003 – R/VAkademik Vavilov 2) 8-14/11/2005 – R/VAkademik Ioffe 3) 16-20/11/2005 – R/VAkademik Ioffe 4) 11-19/11/2007 – R/VAkademik Ioffe 5) 23/10-3/11/2008 – R/VAkademik Vavilov 6) 1-20/1/2010 – R/VAkademik Ioffe
Circulation and upper boundary depth of Weddel Sea Deep Water in the Scotia Sea and Drake Passage
Water exchange in theCircumpolar Bottom Waterlayer across Drk03 and Drk07 sections based on LADCP measurements Nearly zero total transport of CBW, as well as WSDW seen in three sections (2003, 2007, 2010) may indicate that the Shackleton Ridge has significantly greater influence on the deep and bottom water circulation than previously thought
Geostrophic currents in the bottom layer, and virtual pathway of ABW propagation
Hypothetic new mechanism of Antarctic Intermediate Water formation due to the SAF cyclonic eddies
Example of synoptic SSHanomalyin thewesternSouthAtlantic(10.10.2000) showing several cyclonic eddies
Components of the water and salt balances in the layer of Antarctic Intermediate Water in the South Atlantic Notice: Positivevaluesofthe transportsofwaterand salt contentanomaliesmeanflowofwaterintotheboxandsalinificationofwaterinit.Negativevalues mean water outflowandfreshening. 8
3. SHELF CIRCULATION IN SW ATLANTIC, AND ROLE OF LA PLATA DISCHARGE • Zavialov, P.O., O.O. Moller Jr., and E.D. Campos, SAFARI Cruise: Direct Measurements of Currents on South Brazilian Shelf. Continental Shelf Res., 2002. • Zavialov, P.O., A.G. Kostianoy, and O.O. Moller Jr. Tracing Freshwater Discharge Effects on South Brazilian Shelf, Geophys. Res. Letters, doi:10.1029/2003GL018265, 2003.
“Zoo” of temperature inversions in ROFI Typical inversions No inversion (away from ROFI)
SAFARI Cruise: Depth of Tmax, m 15 30 40 50 50
SAFARI Cruise: (Tmax-Tsurf), oC 1 4 3 2 2
SAFARI Cruise: Synthetic TS diagram Cold season temperature anomalies in La Plata ROFI are 70-80% due to air-sea interactions in the presence of buoyancy controlled stratification - and only 20-30% due to mixing with river waters
THANK YOU FOR YOUR ATTENTION