Russian Academy of Sciences

Talk presented at SAMOC-3 Meeting, Rio de Janeiro, Brazil, May 11, 2010

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

Founded: 1946Employees: ~1200Scientists: ~600PhD’s: ~160 DSc’s: ~90Graduate students: ~60Fleet: 6

Biological OceanographyDivision

GeologicalOceanographyDivision

PhysicalOceanographyDivision

OceanEngineeringDivision

6 Labs 13 Labs 13 Labs 7 Labs

P.P.SHIRSHOV INSTITUTE OF OCEANOLOGY (SIO RAS)

+ 5 regional filial branches

Faculty and staff : 108 scientists, 53 engineers, total 161

Graduate students: 17

Publications in 2009: 109 journal aricles, 6 books

SIO RAS PO Division in 2009

Laboratory Head

Ocean-Atmosphere Interactions and Climate Variability S. Gulev

Experimental Physical Oceanography A. Zatsepin

Geophysical Fluid Dynamics G. Reznik

Ocean Optics and Remote Sensing O. Kopelevich

Ocean Acoustics Yu. Chepurin

Noises and Sound Fluctuations in the Ocean A. Vedenev

Internal Waves and Tides E. Morozov

General Ocean Circulation V. Zhmur

Large-Scale Variability of Thermohaline Fields V. Byshev

Continental Discharges and Anthropogenic Impacts P. Zavialov

Turbulence, Mixing, and Microscale Processes V. Zhurbas

Numerical Modeling

Surface Waves and Nonlinear Wave Processes

E. Semenov

V. Zakharov

SIO RAS PO Division in 2009

Ongoing projects of SIO RAS in the seas surrounding Russia

Ongoing projects of SIO RAS in the seas surrounding Russia

1. Antarctic Bottom Water transportthrough SA abyssal channels[E.G.[E.G. Morozov et alMorozov et al..] – ] – multiple publications, multiple publications, 2000-20102000-2010

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

Stations occupied in the Vema Channel

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 Channel

Note 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 m to 4500 m.Agreement with laboratory model experiment.

22. CURRENTS AND WATER MASSES IN THE . CURRENTS AND WATER MASSES IN THE SOUTH ATLANTICSOUTH 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 Abyssal and deep water masses at section Drk03and deep water masses at section Drk03

1) 11-15/12/2003 – R/V Akademik Vavilov 2) 8-14/11/2005 – R/V Akademik Ioffe3) 16-20/11/2005 – R/V Akademik Ioffe 4) 11-19/11/2007 – R/V Akademik Ioffe5) 23/10-3/11/2008 – R/V Akademik Vavilov 6) 1-20/1/2010 – R/V Akademik Ioffe

Circulation and upper boundary depth of Circulation and upper boundary depth of Weddel Sea Deep WaterWeddel Sea Deep Water in the Scotia Sea in the Scotia Sea and Drake Passageand Drake Passage

Water exchange in theWater exchange in the Circumpolar Bottom Circumpolar Bottom WaterWater layer across Drk03 and Drk07 sections layer across Drk03 and Drk07 sections based on LADCP measurementsbased 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

Hydrographic survey of 2008 in Drake PassageHydrographic survey of 2008 in Drake Passage

Geostrophic currents in the bottom layer, Geostrophic currents in the bottom layer, and virtual pathway of ABW propagationand virtual pathway of ABW propagation

Hypothetic new mechanism of Hypothetic new mechanism of Antarctic Antarctic Intermediate WaterIntermediate Water formation due to the SAF formation due to the SAF cyclonic eddiescyclonic eddies

Example of synoptic SSHExample of synoptic SSH anomalyanomaly in thein the westernwestern SouthSouth AtlanticAtlantic (10.10.200010.10.2000) showing ) showing several cyclonic eddiesseveral cyclonic eddies

Balance componentWater

transport,106 m3/с

Transport of salt content anomaly with reference to the

mean salinity of the box, 105 kg/s

Subantarctic Front cyclones 10.0 –17.6

Subantarctic Front anticyclones –1.4 2.2

Agulhas Front anticyclones 13.3 0.5

South Atlantic Current –17.5 5.3

Currents on the northern boundary of the box

–4.9 –3.1

Mixing on the upper boundary of the box – 8.0

Mixing on the lower boundary of the box – 3.3

Isopycnal mixing on the northern boundary of the box

– 2.8

Isopycnal mixing on the open part of the box boundary along 20°E

– –0.2

Vertical advection on the upper boundary of the box

–1.6 –3.6

Vertical advection on the lower boundary of the box 2.1 2.4

Components of the water and salt balances in the layer of Components of the water and salt balances in the layer of Antarctic Intermediate Water in the South AtlanticAntarctic Intermediate Water in the South Atlantic

Notice: Positive values of the transports of water and salt content anomalies mean flow of water into the box and salinification of water in it. Negative values mean water outflow and freshening. 88

• 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.

• 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.

33. SHELF CIRCULATION IN SW ATLANTIC, . SHELF CIRCULATION IN SW ATLANTIC, AND ROLE OF LA PLATA DISCHARGEAND ROLE OF LA PLATA DISCHARGE

Analysis of velocity data collected on SWA shelf

Analysis of velocity data collected on SWA shelf

Northward countercurrent on the SWA shelf

SAFARI Cruise (May 2002)

“Zoo” of temperature inversions in La Plata ROFI

“Zoo” of temperature inversions in ROFI

No inversion (away from ROFI)

Typical inversions

SAFARI Cruise: Depth of Tmax, m

40

50

30

15

50

SAFARI Cruise: (Tmax-Tsurf), oC

2

3

4

1

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