Articles | Volume 11, issue 3
https://doi.org/10.5194/os-11-483-2015
© Author(s) 2015. 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-11-483-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
30 Jun 2015
Research article |
| 30 Jun 2015
Decadal variability and trends of the Benguela upwelling system as simulated in a high-resolution ocean simulation
Helmholtz-Zentrum Geesthacht, Institute of Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht, Germany
E. Zorita
Helmholtz-Zentrum Geesthacht, Institute of Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht, Germany
B. Hünicke
Helmholtz-Zentrum Geesthacht, Institute of Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht, Germany
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Nele Tim, Eduardo Zorita, Kay-Christian Emeis, Franziska U. Schwarzkopf, Arne Biastoch, and Birgit Hünicke
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Oliver Bothe, Sebastian Wagner, and Eduardo Zorita
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Our understanding of future climate changes increases if different sources of information agree on past climate variations. Changing climates particularly impact local scales for which future changes in precipitation are highly uncertain. Here, we use information from observations, model simulations, and climate reconstructions for regional precipitation over the British Isles. We find these do not agree well on precipitation variations over the past few centuries.
Xing Yi, Birgit Hünicke, and Eduardo Zorita
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In this study, we analyse the outputs of Earth System Models to investigate the Arabian Sea upwelling for the last 1000 years and in the 21st century. Due to the orbital forcing of the models, the upwelling in the past is found to reveal a negative long-term trend, which matches the observed sediment records. In the future under the RCP8.5 scenario, the warming of the sea water tends to stabilize the surface layer and thus interrupts the upwelling.
Sitar Karabil, Eduardo Zorita, and Birgit Hünicke
Earth Syst. Dynam., 9, 69–90, https://doi.org/10.5194/esd-9-69-2018, https://doi.org/10.5194/esd-9-69-2018, 2018
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Sitar Karabil, Eduardo Zorita, and Birgit Hünicke
Earth Syst. Dynam., 8, 1031–1046, https://doi.org/10.5194/esd-8-1031-2017, https://doi.org/10.5194/esd-8-1031-2017, 2017
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We statistically analysed the mechanisms of the variability in decadal sea-level trends for the whole Baltic Sea basin over the last century. We used two different sea-level data sets and several climatic data sets. The results of this study showed that precipitation has a lagged effect on decadal sea-level trend variations from which the signature of atmospheric effect is removed. This detected underlying factor is not connected to oceanic forcing driven from the North Atlantic region.
Johann H. Jungclaus, Edouard Bard, Mélanie Baroni, Pascale Braconnot, Jian Cao, Louise P. Chini, Tania Egorova, Michael Evans, J. Fidel González-Rouco, Hugues Goosse, George C. Hurtt, Fortunat Joos, Jed O. Kaplan, Myriam Khodri, Kees Klein Goldewijk, Natalie Krivova, Allegra N. LeGrande, Stephan J. Lorenz, Jürg Luterbacher, Wenmin Man, Amanda C. Maycock, Malte Meinshausen, Anders Moberg, Raimund Muscheler, Christoph Nehrbass-Ahles, Bette I. Otto-Bliesner, Steven J. Phipps, Julia Pongratz, Eugene Rozanov, Gavin A. Schmidt, Hauke Schmidt, Werner Schmutz, Andrew Schurer, Alexander I. Shapiro, Michael Sigl, Jason E. Smerdon, Sami K. Solanki, Claudia Timmreck, Matthew Toohey, Ilya G. Usoskin, Sebastian Wagner, Chi-Ju Wu, Kok Leng Yeo, Davide Zanchettin, Qiong Zhang, and Eduardo Zorita
Geosci. Model Dev., 10, 4005–4033, https://doi.org/10.5194/gmd-10-4005-2017, https://doi.org/10.5194/gmd-10-4005-2017, 2017
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Climate model simulations covering the last millennium provide context for the evolution of the modern climate and for the expected changes during the coming centuries. They can help identify plausible mechanisms underlying palaeoclimatic reconstructions. Here, we describe the forcing boundary conditions and the experimental protocol for simulations covering the pre-industrial millennium. We describe the PMIP4 past1000 simulations as contributions to CMIP6 and additional sensitivity experiments.
Maria Pyrina, Sebastian Wagner, and Eduardo Zorita
Clim. Past, 13, 1339–1354, https://doi.org/10.5194/cp-13-1339-2017, https://doi.org/10.5194/cp-13-1339-2017, 2017
Svenja E. Bierstedt, Birgit Hünicke, Eduardo Zorita, and Juliane Ludwig
Earth Syst. Dynam., 8, 639–652, https://doi.org/10.5194/esd-8-639-2017, https://doi.org/10.5194/esd-8-639-2017, 2017
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We statistically analyse the relationship between the structure of migrating dunes in the southern Baltic and the driving wind conditions over the past 26 years, with the long-term aim of using migrating dunes as a proxy for past wind conditions at an interannual resolution.
Juan José Gómez-Navarro, Eduardo Zorita, Christoph C. Raible, and Raphael Neukom
Clim. Past, 13, 629–648, https://doi.org/10.5194/cp-13-629-2017, https://doi.org/10.5194/cp-13-629-2017, 2017
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This contribution aims at assessing to what extent the analogue method, a classic technique used in other branches of meteorology and climatology, can be used to perform gridded reconstructions of annual temperature based on the limited information from available but un-calibrated proxies spread across different locations of the world. We conclude that it is indeed possible, albeit with certain limitations that render the method comparable to more classic techniques.
Xing Yi and Eduardo Zorita
Clim. Past Discuss., https://doi.org/10.5194/cp-2016-124, https://doi.org/10.5194/cp-2016-124, 2016
Revised manuscript not accepted
Short summary
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In this paper we study the upwelling in the Arabian Sea simulated in two Earth System Models for the last millennium and for the 21st century. Revealing a negative long-term trend due to the model orbital forcing, the upwelling over the last millennium is strongly correlated with the SST, the Indian summer Monsoon and the G.bulloides abundance observed in the sediment records. In the future scenarios the warming of the sea water tends to stabilize the surface layer and hinder the upwelling.
Nele Tim, Eduardo Zorita, Birgit Hünicke, Xing Yi, and Kay-Christian Emeis
Ocean Sci., 12, 807–823, https://doi.org/10.5194/os-12-807-2016, https://doi.org/10.5194/os-12-807-2016, 2016
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The impact of external climate forcing on the four eastern boundary upwelling systems is investigated for the recent past and future. Under increased radiative forcing, upwelling-favourable winds should strengthen due to unequal heating of land and oceans. However, coastal upwelling simulated in ensembles of climate simulations do not show any imprint of external forcing neither for the past millennium nor for the future, with the exception of the strongest future scenario.
Svenja E. Bierstedt, Birgit Hünicke, Eduardo Zorita, Sebastian Wagner, and Juan José Gómez-Navarro
Clim. Past, 12, 317–338, https://doi.org/10.5194/cp-12-317-2016, https://doi.org/10.5194/cp-12-317-2016, 2016
X. Yi, B. Hünicke, N. Tim, and E. Zorita
Ocean Sci. Discuss., https://doi.org/10.5194/osd-12-2683-2015, https://doi.org/10.5194/osd-12-2683-2015, 2015
Revised manuscript not accepted
Short summary
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In this paper, we use the vertical water mass transport data provided by a high-resolution global ocean simulation to study the western Arabian Sea coastal upwelling system. Our results show that: 1). no significant long-term trend is detected in the upwelling time series. 2). the impact of Indian summer monsoon on the simulated upwelling is weak. 3). the upwelling is strongly affected by the sea level pressure gradient and the air temperature gradient.
J. J. Gómez-Navarro, O. Bothe, S. Wagner, E. Zorita, J. P. Werner, J. Luterbacher, C. C. Raible, and J. P Montávez
Clim. Past, 11, 1077–1095, https://doi.org/10.5194/cp-11-1077-2015, https://doi.org/10.5194/cp-11-1077-2015, 2015
J. A. Santos, M. F. Carneiro, A. Correia, M. J. Alcoforado, E. Zorita, and J. J. Gómez-Navarro
Clim. Past, 11, 825–834, https://doi.org/10.5194/cp-11-825-2015, https://doi.org/10.5194/cp-11-825-2015, 2015
J. J. Gómez-Navarro, J. P. Montávez, S. Wagner, and E. Zorita
Clim. Past, 9, 1667–1682, https://doi.org/10.5194/cp-9-1667-2013, https://doi.org/10.5194/cp-9-1667-2013, 2013
G. Esnaola, J. Sáenz, E. Zorita, A. Fontán, V. Valencia, and P. Lazure
Ocean Sci., 9, 655–679, https://doi.org/10.5194/os-9-655-2013, https://doi.org/10.5194/os-9-655-2013, 2013
O. Bothe, J. H. Jungclaus, D. Zanchettin, and E. Zorita
Clim. Past, 9, 1089–1110, https://doi.org/10.5194/cp-9-1089-2013, https://doi.org/10.5194/cp-9-1089-2013, 2013
Cited articles
Bakun, A.: Global climate change and intensification of coastal ocean upwelling, Science, 247, 198–201, https://doi.org/10.1126/science.247.4939.198, 1990.
Bakun, A. and Nelson, C. S.: The seasonal cycle of wind-stress curl in subtropical eastern boundary current regions, J. Phys. Oceanogr., 21, 1815–1834, https://doi.org/10.1175/1520-0485(1991)021<1815:TSCOWS>2.0.CO;2, 1991.
Bakun, A. and Weeks, S. J.: Greenhouse gas builtup, sardines, submarine eruptions and the possibility of abrupt degradation of intense marine upwelling ecosystems, Ecol. Lett., 7, 1015–1023, https://doi.org/10.1111/j.1461-0248.2004.00665.x, 2004.
Bakun, A., Field, D. B., Redondo-Rodriguez, A., and Weeks, S. J.: Greenhouse gas, upwelling-favorable winds, and the future of coastal ocean upwelling ecosystems, Glob. Change Biol., 16, 1213–1228, https://doi.org/10.1111/j.1365-2486.2009.02094.x, 2010.
Belmadani, A., Echevin, V., Codron, F., Takahashi, K., and Junquas, C.: What dynamics drive future wind scenarios for coastal upwelling off Peru and Chile?, Clim. Dynam., 43, 1893–1914, https://doi.org/10.1007/s00382-013-2015-2, 2014.
Blanke, B., Speich, S., Bentamy, A., Roy, C., and Sow, B.: Modelling the structure and variability of the southern Benguela upwelling using QuickSCAT wind forcing, J. Geophys. Res., 110, C07018, https://doi.org/10.1029/2004JC002529, 2005.
Cai, W., Borlace, S., Lengaigne, M., Van Rensch, P., Collins, M., Vecchi, G., Timmermann, A., Santos, A., McPhaden, M. J., Wu, L., England, M. H., Wang, G., Guilyardi, E., and Jin, F.-F.: Increasing frequency of extreme El Niño events due to greenhouse warming, Nature Clim. Change, 4, 111–116, https://doi.org/10.1038/NCLIMATE2100, 2014.
Casey, K. S., Brandon, T. B., Cornillon, P., and Evans, R.: The past, present, and future of the AVHRR pathfinder SST program, in: Oceanography from Space, edited by: Barale, V., Gower, J., and Alberotanza, L., Springer Netherlands, Dordrecht, the Netherlands, 273–287, 2010.
Chaigneau, A., Eldin, G., and Dewitte, B.: Eddy activity in the four major upwelling systems from satellite altimetry (1992–2007), Prog. Oceanogr., 83, 117–123, https://doi.org/10.1016/j.pocean.2009.07.012, 2009.
Chavez, F. P. and Messié, M.: A comparison of eastern boundary upwelling ecosystems, Prog. Oceanogr., 83, 80–96, https://doi.org/10.1016/j.pocean.2009.07.032, 2009.
Chelton, D. B., Schlax, M. G., Freilich, M. H., and Milliff, R. F.: Satellite measurements reveal persistent small-scale features in ocean winds, Science, 303, 978–983, https://doi.org/10.1126/science.1091901, 2004.
Chen, Z., Yan, X.-H., Jo, Y.-H., Jiang, L., and Jiang, Y.: A study of Benguela upwelling system using different upwelling indices derived from remotely sensed data, Cont. Shelf Res., 45, 27–33, https://doi.org/10.1016/j.csr.2012.05.013, 2012.
Chiang, J. C. H. and Vimont, D. J.: Analogous Pacific and Atlantic meridional modes of tropical atmosphere-ocean variability, J. Climate, 17, 4143–4158, https://doi.org/10.1175/JCLI4953.1, 2004.
Colas, F., Capet, X., McWilliam, J. C., and Shchepetkin, A. F.: 1997–1998 El Niño off Peru: A numerical study, Prog. Oceanogr., 79, 138–155, https://doi.org/10.1016/j.pocean.2008.10.015, 2008
Colberg, F. and Reason, C. J. C.: A model study of the Angola Benguela frontal zone: sensitivity to atmospheric forcing, Geophys. Res. Lett., 33, L19608, https://doi.org/10.1029/2006GL027463, 2006.
Dee, D. P., Uppala, S. M., Simmons, A. J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Balmaseda, M. A., Balsamo, G., Bauer, P., Bechtold, P., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S. B., Hersbach, H., Hólm, E. V., Isaksen, L., Kållberg, P., Köhler, M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J.-J., Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thépaut, J.-N., and Vitart, F.: The ERA-Interim reanalysis: configuration and performance of the data assimilation system., Q. J. Roy. Meteor. Soc., 137, 553–597, https://doi.org/10.1002/qj.828, 2011.
Demarq, H.: Trends in primary production, sea surface temperature and wind in upwelling systems (1998–2007), Prog. Oceanogr., 83, 376–385, https://doi.org/10.1016/j.pocean.2009.07.022, 2009.
Deutsch, C., Brix, H., Ito, T., Frenzel, H., and Thompson, L.: Climate-forced variability of ocean hypoxia, Science, 333, 335–339, https://doi.org/10.1126/science.1202422, 2011.
Dufois, F. and Rouault, M.: Sea surface temperature in False Bay (South Africa): towards a better understanding of its seasonal and inter-annual variability, Cont. Shelf Res., 43, 24–35, https://doi.org/10.1016/j.csr.2012.04.009, 2012.
Dufois, F., Penven, P., Whittle, C. P., and Veitch, J.: On the warm nearshore bias in pathfinder monthly SST products over eastern boundary upwelling systems, Ocean Model., 47, 113–118, https://doi.org/10.1016/j.ocemod.2012.01.007, 2012.
Ebisuzaki, W.: A Method to Estimate the Statistical Significance of a Correlation When the Data Are Serially Correlated, J. Climate, 10, 2147–2153, 1997.
Echevin, V., Goubanova, K., Belmadani, A., and Dewitte, B.: Sensitivity of the Humboldt current system to global warming: a downscaling experiment of the IPSL-SM4 model, Clim. Dynam., 38, 761–774, https://doi.org/10.1007/s00382-011-1085-2, 2012.
Feistel, R., Hagen, E., and Grant, K.: Climatic changes in the subtropical Southeast Atlantic: the St. Helena index climate index (1893–1999), Prog. Oceanogr., 59, 321–337, https://doi.org/10.1016./j.pocean.2003.07.002, 2003.
Fennel, W., Junker, T., Schmidt, M., and Mohrholz, V.: Response of the Benguela upwelling systems to spatial variations in the wind stress, Coast. Shelf Res., 45, 65–77, https://doi.org/10.1016/j.csr.2012.06.004, 2012.
Grodsky, S. A., Carton, J. A., and Nigam, S.: Tropical Atlantic biases in CCSM4, J. Climate, 25, 3684–3701, https://doi.org/10.1175/JCLI-D-11-00315.1, 2012.
Hagen, E., Feistel, R., Agenbag, J. J., and Ohde, T.: Seasonal and interannual changes in intense Benguela upwelling (1982–1999), Oceanol. Acta, 24, 557–568, https://doi.org/10.1016/s0399-1784(01)01173-2, 2001.
Hagen, E., Agenbag, J. J., and Feistel, R.: The winter St. Helena climate index and extreme Benguela upwelling, J. Marine Syst., 57, 219–230, https://doi.org/10.1016/j.jmarsys.2005.03.006, 2005.
Ham, Y.-G., Kug, J.-S., and Park, J.-Y.: Two distinct role of Atlantic SSTs in ENSO variability: north tropical Atlantic SST and Atlantic Niño, Geophys. Res. Lett., 40, 4012–4017, https://doi.org/10.1002/grl.50729, 2013.
Hardman-Mountford, N. J., Richardson, A. J., Agenbag, J. J., Hagen, E., Nykjaer, L., Shillington, F. A., and Villacastin C.: Ocean climate of the South East Atlantic observed from satellite data and wind models, Prog. Oceanogr., 59, 181–221, https://doi.org/10.1016/j.pocean.2003.10.001, 2003.
Hartmann, D. L., Klein Tank, A. M. G., Rusticucci, M., Alexander, L. V., Brönnimann, S., Charabi, Y., Dentener, F. J., Dlugokencky, E. J., Easterling, D. R., Kaplan, A., Soden, B. J., Thorne, P. W., Wild, M., and Zhai, P. M.: Observations: atmosphere and surface, in: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, NY, USA, 159–254, 2013.
Huang, H.-P., Robertson, A. W., and Kushnir, Y.: Atlantic SST gradient and the influence of ENSO, Geophys. Res. Lett., 32, L20706, https://doi.org/10.1029/2005GL023944, 2005.
Hutchings, L., van der Lingen, C. D., Shannon, L. J., Crawford, R. J. M., Verheye, H. M. S., Bartholomae, C. H., van der Plas, A. K., Louw, D., Kreiner, A., Ostrowski, M., Fidel, Q., Barlow, R. G., Lamont, T., Coetzee, J., Shillington, F., Veitch, J., Currie, J. C., and Monteiro, P. M. S.: The Benguela current: an ecosystem of four components, Prog. Oceanogr., 83, 15–32, https://doi.org/10.1016/j.pocean.2009.07.046, 2009.
Jenkins, G. M. and Watts, D. G.: Spectral Analysis and its Applications, Holden-Day, San Francisco, USA, 541 pp., 1968.
Jones, J. M. and Widmann, M.: Early peak in Antarctic oscillation index, Nature, 432, 290–291, https://doi.org/10.1038/432290b, 2004.
Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deqaven, D., Gandln, L., Iredell, M., Saha, S., White, G., Woollen, J., Zhu, Y., Chelliah, M., Ebisuzaki, W., Higgins, W., Janowlak, J., Mo, K. C., Ropelewski, C., Wang, J., Leetmaa, A., Reynolds, R., Jenne, R., and Joseph, D.: The NCEP/NCAR 40-year reanalysis project, B. Am. Meteorol. Soc., 77, 437–470, https://doi.org/10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2, 1996.
Kim, S.-T., Cai, W., Jin, F.-F., Santoso, A., Wu, L., Guilyardi, E. and An, S.-I.: Response of El Niño sea surface temperature variability to greenhouse warming, Nature C. C., 4, 786–790, https://doi.org/10.1038/nclimate2326, 2014.
Labitzke, K. and van Loon, H.: Associations between the 11-year solar cycle, the QBO and the atmosphere. Part I: the troposphere and stratosphere in the northern hemisphere in winter, J. Atmos. Terr. Phys., 50, 197–206, https://doi.org/10.1016/0021-9169(88)90068-2, 1988.
Lachkar, Z. and Gruber, N.: A comparative study of biological production in eastern boundary upwelling systems using an artificial neural network, Biogeosciences, 9, 293–308, https://doi.org/10.5194/bg-9-293-2012, 2012.
Latif, M. and Grötzner, A.: The equatorial Atlantic oscillation and its response to ENSO, Clim. Dynam., 16, 213–218, https://doi.org/10.1007/s003820050014, 2000.
Leduc, G., Herbert, C. T., Blanz, T., Martinez, P., and Schneider, R.: Contrasting evolution of sea surface temperature in the Benguela upwelling system under natural and anthropogenic climate forcings, Geophys. Res. Lett., 37, L20705, https://doi.org/10.1029/2010GL044353, 2010.
Li, H. and von Storch, J.-S.: On the fluctuating Buoyancy fluxes simulated in a 1/10° OGCM, J. Phys. Oceanogr., 43, 1270–1287, https://doi.org/10.1175/JPO-D-12-080.1, 2013.
Mackas, D. L., Strub, P. T., Thomas, A., and Montecino, V.: Eastern ocean boundaries pan-regional overview, in: The Sea. The Global Coastal Ocean: Interdisciplinary Regional Studies and Syntheses, edited by: Robinson, A. R. and Brink, K. H., Harvard Press, Cambridge, MA, USA, 21–59, 2006.
Marshall, G. J.: Trends in the southern annular mode from observations and reanalyses, J. Climate, 16, 4134–4143, https://doi.org/10.1175/1520-0442(2003)016<4134:TITSAM>2.0.CO;2, 2003.
Marsland, S. J., Haak, H., Jungclaus, J. H., Latif, M., and Röske, F.: The Max-Planck-Institute global ocean/sea ice model with orthogonal curvilinear coordinates, Ocean Model., 5, 91–127, https://doi.org/10.1016/S1463-5003(02)00015-X, 2003.
McCabe, R. M., Hickey, B. M., Dever, E. P., and MacCready, P.: Seasonal cross-shelf flow structure, upwelling relaxation, and the alongshelf pressure gradient in the Northern California current system, J. Phys. Oceanogr., 45, 209–227, https://doi.org/10.1175/JPO-D-14-0025.1, 2015.
McCartney, M. S.: The subtropical recirculation of mode waters, J. Mar. Res., 40, 427–464, 1982.
Narayan, N., Paul, A., Mulitza, S., and Schulz, M.: Trends in coastal upwelling intensity during the late 20th century, Ocean Sci., 6, 815–823, https://doi.org/10.5194/os-6-815-2010, 2010.
Nelson, G. and Hutchings, L.: The Benguela upwelling area, Prog. Oceanogr., 12, 333–356, https://doi.org/10.1016/0079-6611(83)90013-7, 1983.
Parrish, R. H., Bakun, A., Husby, D. M., and Nelson, C. S.: Comparative climatology of selected environmental processes in relation to eastern boundary current pelagic fish reproduction, in: Proceedings of the Expert Consultation to Examine Changes in Abundance and Species Composition of Neritic Fish Resources, vol. Report 291, edited by: Sharp, G. D. and Csirke, J., Food and Agriculture Organization of the United Nations, Rome, Italy, 731–777, 1983.
Rathmann, J.: Klima- und Zirkulationsvariabilität im südhemisphärischen Afrika seit Beginn des 20. Jahrhunderts, Ph.D. thesis, Dissertation University of Augsburg, Augsburg, 2008.
Rayner, N. A., Parker, D., Horton, E., Folland, C. K., Alexander, L., Rowell, D. P., Kent, E. C., and Kaplan, A.: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century, J. Geophys. Res., 108, 4407, https://doi.org/10.1029/2002JD002670, 2003.
Richter, I. and Xie, S.-P.: On the origin of equatorial Atlantic biases in coupled general circulation models, Clim. Dynam., 31, 587–598, https://doi.org/10.1007/s00382-008-0364-z, 2008.
Richter, I., Behera, S., Masumoto, Y., Taguchi, B., Komori, N., and Yamagata, T.: On the triggering of Benguela Niños: remote equatorial versus local influences, Geophys. Res. Lett., 37, L20604, https://doi.org/10.1029/2010GL044461, 2010.
Richter, I.: Climate model biases in the eastern tropical ocean: causes, impacts and ways forward, WIREs Clim. Change, 6, 345–358, https://doi.org/10.1002/wcc.338, 2015.
Risien, C. M., Reason, C. J. C., and Shillington, F. A.: Variability in satellite winds over the Benguela upwelling system during 1999–2000, J. Geophys. Res., 109, C03010, https://doi.org/10.1029/2003JC001880, 2004.
Risien, C. M., and Chelton, D. B.: A Global Climatology of Surface Wind and Wind Stress Fields from Eight Years of QuickSCAT Scatterometer Data, J. Phys. Oceanogr., 38, 2379–2413, https://doi.org/10.1175/2008JPO3881.1, 2008.
Rodríguez-Fonseca, B., Polo, I., García-Serrano, J., Losada, T., Mohino, E., Mechoso, C. R., and Kucharski, F.: Are Atlantic Niños enhancing Pacific ENSO events in recent decades?, Geophys. Res. Lett., 36, L20705, https://doi.org/10.1029/2009GL040048, 2009.
Rouault, M., Illig, S., Bartholomae, C., Reason, C. J. C., and Bentamy, A.: Propagation and origin of warm anomalies in the Angola Benguela upwelling system in 2001, J. Marine Syst., 68, 573–488, https://doi.org/10.1016/j.jmarsys.2006.11.010, 2007.
Rouault, M., Pohl, B., and Penven, P.: Coastal oceanic climate change and variability from 1982 to 2009 around South Africa, Afr. J. Mar. Sci., 32, 237–246, https://doi.org/10.2989/1814232X.2010.501563, 2010.
Rykaczewski, R. R. and Checkley, D. M.: Influence of ocean winds on the pelagic ecosystem in upwelling regions, P. Natl. Acad. Sci. USA, 105, 1965–1970, 2008.
Serazin, G., Penduff, T., Gregorio, S., Barnier, B., Molines, J., and Terray, L.: Intrinsic variability of sea-level from global 1/12° ocean simulations: spatio-temporal scales. J. Climate, https://doi.org/ 10.1175/JCLI-D-14-00554.1, in press, 2015.
Shannon, L. V.: The Benguela ecosystem Part I: Evolution of the Benguela, physical features and processes, Oceanogr. Mar. Biol., 23, 105–182, 1985.
Shannon, L. V. and Nelson, G.: The Benguela: large scale features and processes and system variability, in: The South Atlantic: Present and Past Circulation, edited by: Wefer, G., Berger, W. H., Siedler, G., and Webb, D. J., Springer-Verlag, Berlin, Heidelberg, Germany, 163–210, 1996.
Shannon, L. V. and O'Toole, M. J.: Sustainability of the Benguela: ex Africa semper aliquid novi, in: Large Marine Ecosystems of the World: Trends in Exploitation, edited by: Hempel, G., and Sherman, K., 227–253, Elsevier, Amsterdam, the Netherlands, 2003.
Shannon, L. V., Boyd, A. J., Brundrit, G. B., and Taunton-Clark, J.: On the existence of an El Niño-type phenomenon in the Benguela system, J. Mar. Res., 44, 495–520, https://doi.org/10.1357/002224086788403105, 1986.
Smith, S. R., Legler, D. M., and Verzone, K. V.: Quantifying Uncertainties in NCEP Reanalyses Using High-Quality Research Vessel Observations, J. Climate, 14, 4062–4072, 2001.
Vecchi, G. A. and Wittenberg, A. T.: El Niño and our future climate: where do we stand?, WIREs Clim. Change, 1, 260–270, https://doi.org/10.1002/wcc.33, 2010.
Vecchi, G. A., Soden, B. J., Wittenberg, A. T., Held, I. M., Leetmaa, A., and Harrison, M. J.: Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing, Nature, 441, 73–76, https://doi.org/10.1038/nature04744, 2006.
Veitch, J., Penven, P., and Shillington, F.: Modeling equilibrium dynamics of Benguela current system, J. Phys. Oceanogr., 40, 1942–1964, https://doi.org/10.1175/2010JPO4382.1, 2010.
von Storch, J.-S., Eden, C., Fast, I., Haak, H., Hernández-Deckers, D., Maier-Reimer, E., Marotzke, J., and Stammer, D.: An estimate of the Lorenz energy cycle for the world ocean based on the 1/10° STORM/NCEP simulation, J. Phys. Oceanogr., 42, 2185–2205, https://doi.org/10.1175/JPO-D-12-079.1, 2012.
Wang, C.: An overlooked feature of tropical climate: inter-Pacific-Atlantic variability, Geophys. Res. Lett., 33, L12702, https://doi.org/10.1029/2006GL026324, 2006.
Wang, D., Tarik, C., Gouhier, T. C., Menge, B. A., and Ganguly, A. R.: Intensification and spatial homogenization of coastal upwelling under climate change, Nature 518, 390–394 https://doi.org/10.1038/nature14235, 2015.
Wolter, K. and Timlin, M. S. (Eds.): Monitoring ENSO in COADS with a Seasonally Adjusted Principal Component Index, in: Proceedings of the 17th Climate Diagnostics Workshop, Norman, OK, NOAA/NMC/CAC, NSSL, Oklahoma Climate Survec, CIMMS and the School of Meteorology, University of Oklahoma, Norman, OK, USA, 52–57, 1993.
Short summary
The atmospheric drivers of the Benguela upwelling systems and its variability are statistically analysed with an ocean-only simulation over the last decades. Atmospheric upwelling-favourable conditions are southerly wind/wind stress, a strong subtropical anticyclone, and an ocean-land sea level pressure gradient as well as a negative ENSO and a positive AAO phase. No long-term trends of upwelling and of ocean-minus-land air pressure gradients, as supposed by Bakun, can be seen in our analysis.
The atmospheric drivers of the Benguela upwelling systems and its variability are statistically...
