Articles | Volume 13, issue 1
https://doi.org/10.5194/os-13-175-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/os-13-175-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Characteristics and causes of Deep Western Boundary Current transport variability at 34.5° S during 2009–2014
Christopher S. Meinen
CORRESPONDING AUTHOR
Physical Oceanography Division, Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
Silvia L. Garzoli
Cooperative Institute for Marine and Atmospheric Studies, University
of Miami, Miami, Florida, USA
Physical Oceanography Division, Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
Renellys C. Perez
Cooperative Institute for Marine and Atmospheric Studies, University
of Miami, Miami, Florida, USA
Physical Oceanography Division, Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
Edmo Campos
Instituto Oceanográfico, University of São Paulo, São Paulo, Brazil
Cooperative Institute for Marine and Atmospheric Studies, University
of Miami, Miami, Florida, USA
Alberto R. Piola
Departamento Oceanografia, Servicio de Hidrografía Naval, Buenos Aires, Argentina
Departamento Oceanografia, Universidad de Buenos Aires, Buenos Aires, Argentina
Instituto Franco-Argentino sobre Estudios de Clima y sus Impactos,
Consejo Nacional de Investigaciones Científicas y Técnicas
(CONICET), Argentina
Maria Paz Chidichimo
Departamento Oceanografia, Servicio de Hidrografía Naval, Buenos Aires, Argentina
Departamento Oceanografia, Universidad de Buenos Aires, Buenos Aires, Argentina
Instituto Franco-Argentino sobre Estudios de Clima y sus Impactos,
Consejo Nacional de Investigaciones Científicas y Técnicas
(CONICET), Argentina
Shenfu Dong
Physical Oceanography Division, Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
Olga T. Sato
Instituto Oceanográfico, University of São Paulo, São Paulo, Brazil
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Cited articles
Ansorge I., Baringer, M., Campos, E., Dong, S., Fine, R. A., Garzoli, S., Goni, G., Meinen, C., Perez, R., Piola, A., Roberts, M., Speich, S., Sprintall, J., Terre, T., and van den Berg, M.: Basin-Wide Oceanographic Array Bridges the South Atlantic, EOS Transactions, AGU, 95, 53–54, https://doi.org/10.1002/2014EO060001, 2014.
Arhan, M., Mercier, H., and Park, Y.-H.: On the deep water circulation of the eastern South Atlantic Ocean, Deep-Sea Res. Pt. I, 50, 889–916, https://doi.org/10.1016/S0967-0637(03)00072-4, 2003.
Bryden, H. L., King, B. A., and McCarthy, G. D.: South Atlantic overturning circulation at 24° S, J. Mar. Res., 69, 39–56, https://doi.org/10.1357/002224011798147633, 2011.
Buckley, M. W. and Marshall, J.: Observations, inferences, and mechanisms of the Atlantic Meridional Overturning Circulation: A review, Rev. Geophys., 54, 5–63, https://doi.org/10.1002/2015RG000493, 2016.
Chelton, D. B. and Schlax, M. G.: Global observations of oceanic Rossby Waves, Science, 271, 234–238, 1996.
Chelton, D. B., Schlax, M. G., Samelson, R. M., and de Szoeke, R. A.: Global observations of large oceanic eddies, Geophys. Res. Lett., 34, L15606, https://doi.org/10.1029/2007GL030812, 2007.
Chin, T. M., Milliff, R. F., and Large, W. G.: Basin-Scale, High-Wavenumber Sea Surface Wind Fields from a Multiresolution Analysis of Scatterometer Data, J. Atmos. Ocean. Tech., 15, 741–763, 1998.
Coles, V. J., McCartney, M. S., Olson, D. B., and Smethie Jr., W. M.: Changes in Antarctic Bottom Water properties in the western South Atlantic in the late 1980s, J. Geophys. Res., 101, 8957–8970, 1996.
De Leon, Y. and Paldor, N.: Linear waves in midlatitudes on the rotating spherical Earth, J. Phys. Oceanogr., 39, 3204–3215, https://doi.org/10.1175/2009JPO4083.1, 2009.
Dengler, M., Schott, F. A., Eden, C., Brandt, P., Fischer, J., and Zantopp, R.: Break-up of the Atlantic Deep Western Boundary Current into eddies at 8° S, Nature, 432, 1018–1020, https://doi.org/10.1038/nature03134, 2004.
Dewar, W. K. and Bane, J. M.: Subsurface Energetics of the Gulf Stream near the Charleston Bump, J. Phys. Oceanogr., 15, 1771–1789, 1985.
Dijkstra, H. A.: Characterization of the multiple equilibria regime in a global ocean model, Tellus A, 59, 695–705, 2007.
Dong, S., Garzoli, S. L., Baringer, M. O., Meinen, C. S., and Goni, G. J.: The Atlantic Meridional Overturning Circulation and its Northward Heat Transport in the South Atlantic, Geophys. Res. Lett., 36, L20606, https://doi.org/10.1029/2009GL039356, 2009.
Dong, S., Garzoli, S. L., and Baringer, M. O.: The role of inter-ocean exchanges on decadal variations of the northward heat transport in the South Atlantic, J. Phys. Oceanogr., 41, 1498–1511, 2011.
Dong, S., Baringer, M. O., Goni, G. J., Meinen, C. S., and Garzoli, S. L.: Seasonal variations in the South Atlantic Meridional Overturning Circulation from observations and numerical models, Geophys. Res. Lett., 41, 4611–4618, https://doi.org/10.1002/2014GL060428, 2014.
Dong, S., Goni, G., and Bringas, F.: Temporal variability of the Meridional Overturning Circulation in the South Atlantic between 20° S and 35° S, Geophys. Res. Lett., 42, 7655–7662, https://doi.org/10.1002/2015GL065603, 2015.
Donohue, K. D., Watts, D. R., Tracey, K. L., Greene, A. D., and Kennelly, M.: Mapping circulation in the Kuroshio Extension with an array of current and pressure recording inverted echo sounders, J. Atmos. Ocean. Tech., 27, 507–527, https://doi.org/10.1175/2009JTECHO686.1, 2010.
Drijfhout, S. S., Weber, S. L., and van der Swaluw, E.: The stability of the MOC as diagnosed from model projections for pre-industrial, present and future climates, Clim. Dynam., 37, 1575–1586, https://doi.org/10.1007/s00382-010-0930-z, 2011.
Emery, W. J. and Thomson, R. E.: Data Analysis Methods in Physical Oceanography, Pergamon, Oxford, UK, 1997.
Frajka-Williams, E., Cunningham, S. A., Bryden, H. L., and King, B. A.: Variability of Antarctic Bottom Water at 24.5° N in the Atlantic, J. Geophys. Res., 116, C11026, https://doi.org/10.1029/2011JC007168, 2011.
Frajka-Williams, E., Meinen, C. S., Johns, W. E., Smeed, D. A., Duchez, A., Lawrence, A. J., Cuthbertson, D. A., McCarthy, G. D., Bryden, H. L., Baringer, M. O., Moat, B. I., and Rayner, D.: Compensation between meridional flow components of the Atlantic MOC at 26° N, Ocean Sci., 12, 481–493, https://doi.org/10.5194/os-12-481-2016, 2016.
Ganachaud, A. and Wunsch, C.: Large-Scale Ocean Heat and Freshwater Transports during the World Ocean Circulation Experiment, J. Climate, 16, 696–705, 2003.
Garzoli, S. and Simionato, C.: Baroclinic instabilities and forced oscillations in the Brazil/Malvinas confluence front, Deep-Sea Res., 37 1053–1074, 1990.
Garzoli, S. L.: Geostrophic velocity and transport variability in the Brazil-Malvinas Confluence, Deep-Sea Res. Pt. I, 40, 1379–1403, 1993.
Garzoli, S. L. and Baringer, M. O.: Meridional heat transport determined with expendable bathythermographs, Part II: South Atlantic transport, Deep-Sea Res. Pt. I, 54, 1402–1420, 2007.
Garzoli, S. L. and Matano, R.: The South Atlantic and the Atlantic Meridional Overturning Circulation, Deep-Sea Res. Pt. II, 58, 1837–1847, https://doi.org/10.1016/j.dsr2.2010.10.063, 2011.
Garzoli, S., Baringer, M. O., Dong, S., Perez, R., and Yao, Q.: South Atlantic meridional fluxes, Deep-Sea Res. Pt. I, 71, 21–32, https://doi.org/10.1016/j.dsr.2012.09.003, 2013.
Garzoli, S. L., Dong, S., Fine, R., Meinen, C., Perez, R. C., Schmid, C., van Sebille, E., and Yao, Q.: The fate of the Deep Western Boundary Current in the South Atlantic, Deep-Sea Res. Pt. I, 103, 125–136, https://doi.org/10.1016/j.dsr.2015.05.008, 2015.
Goni, G., Kamholz, S., Garzoli, S., and Olson, D.: Dynamics of the Brazil-Malvinas Confluence based on inverted echo sounders and altimetry, J. Geophys. Res., 101, 16273–16289, 1996.
Goni, G. J., Bringas, F., and DiNezio, P. N.: Observed low frequency variability of the Brazil Current front, J. Geophys. Res., 116, C10037, https://doi.org/10.1029/2011JC007198, 2011.
Gordon, A. L. and Greengrove, C. L.: Geostrophic circulation of the Brazil-Falkland confluence, Deep-Sea Res., 33, 573–585, 1986.
Hogg, N. G. and Owens, W. B.: Direct measurement of the deep circulation within the Brazil Basin, Deep-Sea Res. Pt. II, 46, 335–353, 1999.
Hogg, N. G. and Thurnherr, A. M.: A Zonal Pathway for NADW in the South Atlantic, J. Oceanogr., 61, 493–507, https://doi.org/10.1007/s10872-005-0058-7, 2005.
Hogg, N. G., Siedler, G., and Zenk, W.: Circulation and Variability at the Southern Boundary of the Brazil Basin, J. Phys. Oceanogr., 29, 145–157, 1999.
Hummels, R., Brandt, P., Dengler, M., Fischer, J., Araujo, M., Veleda, D., and Durgadoo, J. V.: Interannual to decadal changes in the western boundary circulation in the Atlantic at 11° S, Geophys. Res. Lett., 42, 7615–7622, https://doi.org/10.1002/2015GL065254, 2015.
Johns, W. E., Beal, L. M., Baringer, M. O., Molina, J. R., Cunningham, S. A., Kanzow, T., and Rayner, D.: Variability of Shallow and Deep Western Boundary Currents off the Bahamas during 2004–05: Results from the 26° N RAPID–MOC array, J. Phys. Oceanogr., 38, 605–623, https://doi.org/10.1175/2007JPO3791.1, 2008.
Johns, W. E., Baringer, M. O., Beal, L. M., Cunningham, S. A., Kanzow, T., Bryden, H. L., Hirschi, J. J. M., Marotzke, J., Meinen, C. S., Shaw, B., and Curry, R.: Continuous, Array-Based Estimates of Atlantic Ocean Heat Transport at 26.5° N, J. Climate, 24, 2429–2449, https://doi.org/10.1175/2010JCLI3997.1, 2011.
Latif, M., Keenlyside, N., and Bader, J.: Tropical sea surface temperature, wind shear, and hurricane development, Geophys. Res. Lett., 34, L01710, https://doi.org/10.1029/2006GL027969, 2007.
Lopez, H., Dong, S., Lee, S.-K., and Goni, G.: Decadal Modulations of Interhemispheric Global Atmospheric Circulations and Monsoons by the South Atlantic Meridional Overturning Circulation, J. Climate, 29, 1831–1851, https://doi.org/10.1175/JCLI-D-15-0491.1, 2016.
Lumpkin, R. and Speer, K.: Large-scale vertical and horizontal circulation in the North Atlantic Ocean, J. Phys. Oceanogr., 33, 1902–1920, https://doi.org/10.1175/1520-0485(2003)033<1902:LVAHCI>2.0.CO;2, 2003.
Lumpkin, R. and Speer, K.: Global Ocean Meridional Overturning, J. Phys. Oceanogr., 37, 2550–2562, https://doi.org/10.1175/JPO3130.1, 2007.
Lumpkin, R. and Garzoli, S.: Interannual to decadal changes in the western South Atlantic's surface circulation, J. Geophys. Res., 116, C01014, https://doi.org/10.1029/2010JC006285, 2011.
Majumder, S., Schmid, C., and Halliwell, G.: An observations and model-based analysis of meridional transport in the South Atlantic, J. Geophys. Res.-Oceans, 121, 5622–5638, https://doi.org/10.1002/2016JC011693, 2016.
Masumoto, Y., Sasaki, H., Kagimoto, T., Komori, N., Ishida, A., Sasai, Y., Miyama, T., Motoi, T., Mitsudera, H., Takahashi, K., Sakuma, H., and Yamagata, T.: A fifty-year Eddy resolving simulation of the world ocean – Preliminary outcomes of OFES (OGCM for the Earth simulator), J. Earth Simulator, 1, 35–56, 2004.
Matano, R. P.: On the separation of the Brazil Current from the coast, J. Phys. Oceanogr., 23, 79–90, https://doi.org/10.1175/1520-0485(1993)023<0079:OTSOTB>2.0.CO;2, 1993.
McCarthy, G. D., Haigh, I. D., Hirschi, J. J., Grist, J. P., and Smeed, D. A.: Ocean impact on decadal Atlantic climate variability revealed by sea-level observations, Nature, 521, 508–510, https://doi.org/10.1038/nature14491, 2015.
Meinen, C. S. and Watts, D. R.: Calibrating Inverted Echo Sounders equipped with Pressure Sensors, J. Atmos. Ocean. Tech., 15, 1339–1345, 1998.
Meinen, C. S. and Watts, D. R.: Vertical structure and transport on a Transect across the North Atlantic Current near 42° N: Time series and mean, J. Geophys. Res., 105, 21869–21892, 2000.
Meinen, C. S., Baringer, M. O., and Garzoli, S. L.: Variability in Deep Western Boundary Current transports: Preliminary results from 26.5° N in the Atlantic, Geophys. Res. Lett., 33, L17610, https://doi.org/10.1029/2006GL026965, 2006.
Meinen, C. S., Piola, A. R., Perez, R. C., and Garzoli, S. L.: Deep Western Boundary Current transport variability in the South Atlantic: preliminary results from a pilot array at 34.5° S, Ocean Sci., 8, 1041–1054, https://doi.org/10.5194/os-8-1041-2012, 2012.
Meinen, C. S., Johns, W. E., Garzoli, S. L., Van Sebille, E., Rayner, D., Kanzow, T., and Baringer, M. O.: Variability of the Deep Western Boundary Current at 26.5° N during 2004–2009, Deep-Sea Res. Pt. II, 85, 154–168, https://doi.org/10.1016/j.dsr2.2012.07.036, 2013a.
Meinen, C. S., Speich, S., Perez, R. C., Dong, S., Piola, A. R., Garzoli, S. L., Baringer, M. O., Gladyshev, S., and Campos, E. J. D.: Temporal variability of the Meridional Overturning Circulation at 34.5° S: Results from two pilot boundary arrays in the South Atlantic, J. Geophys. Res.-Oceans, 118, 6461–6478, https://doi.org/10.1002/2013JC009228, 2013b.
Mémery, L., Arhan, M., Alvarez-Salgado, X. A., Messias, M.-J., Mercier, H., Castro, C. G., and Rios, A. F.: The water masses along the western boundary of the south and equatorial Atlantic, Prog. Oceanogr., 47, 69–98, 2000.
North, G. R., Bell, T. L., Cahalan, R. F., and Moeng, F. J.: Sampling Errors in the Estimation of Empirical Orthogonal Functions, Mon. Weather Rev., 110, 699–706, 1982.
Olson, D. B., Podesta, G. P., Evans, R. H., and Brown, O. B.: Temporal variations in the separation of Brazil and Malvinas Currents, Deep-Sea Res., 35, 1971–1990, 1988.
Osychny, V. and Cornillon, P.: Properties of Rossby Waves in the North Atlantic estimated from satellite data, J. Phys. Oceanogr., 34, 61–76, 2004.
Paldor, N., Rubin, S., and Mariano, A. J.: A consistent theory for linear waves of the Shallow-Water equations on a rotating plane in midlatitudes, 37, 115–128, https://doi.org/10.1175/JPO2986.1, 2007.
Perez, R. C., Garzoli, S. L., Meinen, C. S., and Matano, R. P.: Geostrophic velocity measurement techniques for the meridional overturning circulation and meridional heat transport in the South Atlantic, J. Atmos. Ocean. Tech., 28, 1504–1521, https://doi.org/10.1175/JTECH-D-11-00058.1, 2011.
Perez, R. C., Baringer, M. O., Dong, S., Garzoli, S. L., Goes, M., Goni, G. J., Lumpkin, R., Meinen, C. S., Msadek, R., and Rivero, U.: Measuring the Atlantic meridional overturning circulation, Mar. Technol. Soc. J., 49, 167–177, https://doi.org/10.4031/MTSJ.49.2.14, 2015.
Polito, P. S. and Liu, W. T.: Global characterization of Rossby waves at several spectral bands, J. Geophys. Res., 108, 3018, https://doi.org/10.1029/2000JC000607, 2003.
Polito, P. S. and Sato, O. T.: Do eddies ride on Rossby waves?, J. Geophys. Res., 120, 5417–5435, https://doi.org/10.1002/2015JC010737, 2015.
Preu, B., Hernández-Molina, F. J., Violante, R., Piola, A. R., Paterlini, C. M., Schwenk, T., Voigt, I., Krastel, S., and Spiess, V.: Morphosedimentary and hydrographic features of the northern Argentine margin: The interplay between erosive, depositional and gravitational processes and its conceptual implications, Deep-Sea Res. Pt. I, 75, 157–174, https://doi.org/10.1016/j.dsr.2012.12.013, 2013.
Rossby, T.: On monitoring depth variations of the main thermocline acoustically, J. Geophys. Res., 74, 5542–5546, 1969.
Saraceno, M., Provost, C., Piola, A. R., Bava, J., and Gagliardini, A.: Brazil Malvinas Frontal System as seen from 9 years of advanced very high resolution radiometer data, J. Geophys. Res., 109, C05027, https://doi.org/10.1029/2003JC002127, 2004.
Sasaki, H., Nonaka, M., Sasai, Y., Uehara, H., and Sakuma, H.: An eddy-resolving hindcast simulation of the quasiglobal ocean from 1950 to 2003 on the Earth simulator, in: High Resolution Numerical Modelling of the Atmosphere and Ocean, edited by: Hamilton, K. and Ohfuchi, W., 157–185, Springer, New York, 2008.
Schmid, C.: Mean vertical and horizontal structure of the subtropical circulation in the South Atlantic from three-dimensional observed velocity fields, Deep-Sea Res. Pt. I, 91, 50–71, https://doi.org/10.1016/j.dsr.2014.04.015, 2014.
Schott, F. A., Zantopp, R., Stramma, L., Dengler, M., Fischer, J., and Wibaux, M.: Circulation and deep-water export at the western exit of the Subpolar North Atlantic, J. Phys. Oceanogr., 34, 817–843, 2004.
Schott, F. A., Dengler, M., Zantopp, R., Stramma, L., Fischer, J., and Brandt, P.: The Shallow and deep western boundary circulation of the South Atlantic at 5–11° S, J. Phys. Oceanogr., 35, 2031–2053, https://doi.org/10.1175/JPO2813.1, 2005.
Smith, W. H. F., and Sandwell, D. T.: Global Sea Floor Topography from Satellite Altimetry and Ship Depth Soundings, Science, 277 (5334), l956-1962, 1997.
Srokosz, M. A., and Bryden, H. L.: Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises, Science, 348 (6241), https://doi.org/10.1126/science.1255575, 2015.
Stouffer, R. J., Yin, J., and Gregory, J. M.: Investigating the causes of the response of the thermohaline circulation to past and future climate changes, J. Climate, 19, 1365–1387, 2006.
Toole, J. M., Curry, R. G., Joyce, T. M., McCartney, M., and Peña-Molino, B.: Transport of the North Atlantic Deep Western Boundary Current about 39° N, 70° W: 2004–2008, Deep-Sea Res. Pt. II, 58, 1768–1780, 2011.
Tracey, K. L. and Watts, D. R.: On Gulf Steam meander characteristics near Cape Hatteras, J. Geophys. Res., 91, 7587–7602, 1986.
Trenberth, K. E., Caron, J. M., and Stepaniak, D. P.: The atmospheric energy budget and implications for surface fluxes and ocean heat transports, Clim. Dynam., 17, 259–276, 2001.
van Sebille, E., Johns, W. E., and Beal, L. M.: Does the vorticity flux from Agulhas rings control the zonal pathway of NADW across the South Atlantic?, J. Geophys Res., 117, C05037, https://doi.org/10.1029/2011JC007684, 2012.
Vellinga, M. and Wood, R. A.: Global climatic impacts of a collapse of the Atlantic thermohaline circulation, Climatic Change, 54, 251–267, 2002.
Watts, D. R. and Kontoyiannis, H.: Deep-ocean bottom pressure measurement: Drift Removal and performance, J. Atmos. Ocean. Tech., 7, 296–306, 1990.
Watts, D. R. and Rossby, H. T.: Measuring dynamic heights with inverted echo sounders: Results from MODE, J. Phys. Oceanogr., 7, 345–358, 1977.
Zangenberg, N., and Siedler, G.: The path of the North Atlantic Deep Water in the Brazil Basin, J. Geophys Res., 103, 5419–5428, 1998.
Short summary
This study investigates the variability of the Deep Western Boundary Current at 34.5° S. This current carries a large part of the cold deep limb of the Meridional Overturning Circulation, which is a crucial part of the ocean system and has impacts on global weather patterns. Study of this current in the South Atlantic has been limited in the past, and this new study provides insights into the strength and variability of the current as well as the causes for the observed changes.
This study investigates the variability of the Deep Western Boundary Current at 34.5° S. This...