Articles | Volume 16, issue 6
https://doi.org/10.5194/os-16-1529-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-16-1529-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Marine climate change over the eastern Agulhas Bank of South Africa
Mark R. Jury
CORRESPONDING AUTHOR
Geography Dept., University of Zululand, KwaDlangezwa 3886, South
Africa
Physics Dept., University of Puerto Rico – Mayagüez, Mayagüez, Puerto Rico 00681, USA
Related authors
Mark R. Jury
Adv. Stat. Clim. Meteorol. Oceanogr., 10, 95–104, https://doi.org/10.5194/ascmo-10-95-2024, https://doi.org/10.5194/ascmo-10-95-2024, 2024
Short summary
Short summary
A unique link is found between the Caribbean GDP growth rate and the tropical climate system. Although the Pacific El Niño–Southern Oscillation governs some aspects of this link, the Walker circulation and associated humidity over the equatorial Atlantic emerge as leading predictors of economic prosperity in the central Antilles islands.
Mark R. Jury
Ocean Sci., 16, 1545–1557, https://doi.org/10.5194/os-16-1545-2020, https://doi.org/10.5194/os-16-1545-2020, 2020
Short summary
Short summary
Mesoscale datasets are used to study coastal gradients in the marine climate and oceanography of False Bay, south of Cape Town. Building on past work, satellite and ocean–atmosphere reanalyses are used to gain new insights into the mean structure, circulation and meteorological features. HYCOM v3 hindcasts represent a coastward reduction of mixing that enhances stratification and productivity in False Bay during summer.
Mark R. Jury
Ocean Sci., 15, 1579–1592, https://doi.org/10.5194/os-15-1579-2019, https://doi.org/10.5194/os-15-1579-2019, 2019
Short summary
Short summary
This research considers the physical environmental factors that underpin changes in ocean productivity over the shelf of South Africa, where coastal upwelling occurs next to a warm current. Statistical analysis of model assimilated data show that salinity and wind play prominent roles in changes of chlorophyll content, with possible consequences for the coastal fishery.
Mark R. Jury
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2018-223, https://doi.org/10.5194/hess-2018-223, 2018
Preprint withdrawn
Short summary
Short summary
The climatic processes underlying drought in the SW Cape of South Africa are outlined. The area lies at the transition between the mid-latitude and sub-tropical regimes (34 S). There has been a gradual shift towards increased easterlies, longer dry summers and shorter wet winters. Consequently, water resources near Cape Town are drying up. High-resolution satellite reanalysis of land surface temperature and rainfall reveal the desiccating trends.
Mark R. Jury
Adv. Stat. Clim. Meteorol. Oceanogr., 10, 95–104, https://doi.org/10.5194/ascmo-10-95-2024, https://doi.org/10.5194/ascmo-10-95-2024, 2024
Short summary
Short summary
A unique link is found between the Caribbean GDP growth rate and the tropical climate system. Although the Pacific El Niño–Southern Oscillation governs some aspects of this link, the Walker circulation and associated humidity over the equatorial Atlantic emerge as leading predictors of economic prosperity in the central Antilles islands.
Mark R. Jury
Ocean Sci., 16, 1545–1557, https://doi.org/10.5194/os-16-1545-2020, https://doi.org/10.5194/os-16-1545-2020, 2020
Short summary
Short summary
Mesoscale datasets are used to study coastal gradients in the marine climate and oceanography of False Bay, south of Cape Town. Building on past work, satellite and ocean–atmosphere reanalyses are used to gain new insights into the mean structure, circulation and meteorological features. HYCOM v3 hindcasts represent a coastward reduction of mixing that enhances stratification and productivity in False Bay during summer.
Mark R. Jury
Ocean Sci., 15, 1579–1592, https://doi.org/10.5194/os-15-1579-2019, https://doi.org/10.5194/os-15-1579-2019, 2019
Short summary
Short summary
This research considers the physical environmental factors that underpin changes in ocean productivity over the shelf of South Africa, where coastal upwelling occurs next to a warm current. Statistical analysis of model assimilated data show that salinity and wind play prominent roles in changes of chlorophyll content, with possible consequences for the coastal fishery.
Mark R. Jury
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2018-223, https://doi.org/10.5194/hess-2018-223, 2018
Preprint withdrawn
Short summary
Short summary
The climatic processes underlying drought in the SW Cape of South Africa are outlined. The area lies at the transition between the mid-latitude and sub-tropical regimes (34 S). There has been a gradual shift towards increased easterlies, longer dry summers and shorter wet winters. Consequently, water resources near Cape Town are drying up. High-resolution satellite reanalysis of land surface temperature and rainfall reveal the desiccating trends.
Cited articles
Arblaster, J. M., Meehl, G., and Karoly, D.: Future climate change in the
southern hemisphere: Competing effects of ozone and greenhouse gases,
Geophys. Res. Lett., 38, L02701, https://doi.org/10.1029/2010GL045384, 2011.
Backeberg, B., Penven, P., and Rouault, M.: Impact of intensified Indian Ocean winds on mesoscale variability in the Agulhas system, Nature Clim. Change, 2, 608–612, 2012.
Balmaseda, M. A., Mogensena, K., and Weaver, A. T.: Evaluation of the ECMWF ocean reanalysis system ORAS4, Q. J. Roy. Meteor. Soc., 139, 1132–1161, 2013.
Carton, J. A., Chepurin, G. A., and Chen, L.: SODA-3: A new ocean climate
reanalysis, J. Climate, 31, 6967–6983, 2018.
Chaudhuri, A. H., Ponte, R. M., Forget, G., and Heimbach, P.: A comparison of
atmospheric reanalysis surface products over the ocean and implications for
uncertainties in air–sea boundary forcing, J. Climate, 26, 153–170, 2013.
Collins, W. J., Bellouin, N., Doutriaux-Boucher, M., Gedney, N., Halloran, P., Hinton, T., Hughes, J., Jones, C. D., Joshi, M., Liddicoat, S., Martin, G., O'Connor, F., Rae, J., Senior, C., Sitch, S., Totterdell, I., Wiltshire, A., and Woodward, S.: Development and evaluation of an Earth-System model – HadGEM2, Geosci. Model Dev., 4, 1051–1075, https://doi.org/10.5194/gmd-4-1051-2011, 2011.
Decker, M., Brunke, M. A., Wang, Z., Sakaguchi, K., Zeng, X., and Bosilovich,
M. G.: Evaluation of the reanalysis products from GSFC, NCEP, and ECMWF using
flux tower observations, J. Climate, 25, 1916–1944, 2012.
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, 2011.
Dieppois, B., Rouault, M., and New, M.: The impact of ENSO on Southern African rainfall in CMIP5 ocean atmosphere coupled climate models, Climate Dyn., 45, 2425–2442, 2015.
Dlomo, X.: Sea surface temperature trends around Southern Africa, MSc
thesis, Univ. Cape Town, 61 pp., 2014.
Doblas-Reyes, F. J., Acosta-Navarro, J. C., Acosta, M., Bellprat, O., Bilbao,
R., Castrillo, M., Fuckar, N., Guemas, V., Lledo, L., Menegoz, M.,
Prodhomme, C., Serradell, K., Tinto, O., Batte, L., Volpi, D., Ceglar, A.,
Haarsma, R., Massonnet, F.: Using EC-Earth for climate prediction research,
ECMWF newsletter 154, available at: https://www.ecmwf.int/en/newsletter/154/meteorology/ (last access: 11 May 2020), 2018.
Durgadoo, J. V., Loveday, B. R., Reason, C. J., Penven, P., and Biastoch, A.:
Agulhas leakage predominantly responds to the Southern Hemisphere
westerlies, J. Phys. Oceanogr., 43, 2113–2131, 2013.
Elipot, S. and Beal, L. M.: Characteristics, energetics and origins of Agulhas Current meanders and their limited influence on ring shedding, J. Phys. Oceanogr, 45, 2294–2314, 2015.
Elipot, S. and Beal, L. M.: Observed Agulhas Current sensitivity to interannual and long-term trend atmospheric forcings, J. Climate, 31, 3077–3098, 2018.
Funk, C. C., Peterson, P. J., Landsfeld, M. F., Pedreros, D. H., Verdin, J. P., Rowland, J. D., Romero, B. E., Husak, G. J., Michaelsen, J. C., and Verdin, A. P.: A quasi-global precipitation time series for drought monitoring, US. Geol. Survey Data Series, 832, 1–4, https://doi.org/10.110.3133/ds832, 2014.
Gelaro, R., McCarty, W., Suárez, M. J., Todling, R., Molod, A., Takacs,
L., Randles, C. A., Darmenov, A., Bosilovich, M. G., Reichle, R., Wargan, K.,
Coy, L., Cullather, R., Draper, C., Akella, S., Buchard, V., Conaty, A.,
da Silva, A. M., Gu, W., Kim, G.-K., Koster, R., Lucchesi, R., Merkova, D.,
Nielsen, J. E., Partyka, G., Pawson, S., Putman, W., Rienecker, M., Schubert,
S. D., Sienkiewicz, M., and Zhao, B.: The Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), J. Climate, 30, 5419–5454, 2017.
Goschen, W. S. and Schumann, E. H.: Agulhas Current variability and inshore
structures off the Cape Province, South Africa, J. Geophys. Res., 95,
667–678, 1990.
Goschen, W. S., Bornman, T. G., Deyzel, S. H. P., and Schumann, E. H.: Coastal upwelling on the far eastern Agulhas Bank associated with large meanders in the Agulhas Current, Cont. Shelf Res., 101, 34–46, 2015.
Hamrud, M., Bonavita, M., and Isaksen, L.: Kalman filter and hybrid-gain
ensemble data assimilation. Part I: EnKF implementation, Mon. Weather Rev.,
143, 4847–4864, 2015.
Hutchinson, K., Beal, L. M., Penven, P., Ansorge, I., and Hermes, J.: Seasonal phasing of Agulhas Current transport tied to a baroclinic adjustment of near-field winds, J. Geophys. Res.-Oceans, 123, 7067–7083, 2018.
Jamstec (Japan agency for marine - earth science and technology): Ocean general circulation model for the (University of Hawaii)
earth simulator, GODAS MOMv3 basis, https://doi.org/10.17596/0002029, 2009.
Jury, M. R.: Climate trends in southern Africa, S. Afr. J. Science, 109,
53–63, 2013.
Jury, M. R.: Passive suppression of South African rainfall by the Agulhas
Current, Earth Int., 19, 1–14, 2015.
Jury, M. R.: Environmental controls on marine productivity near Cape St. Francis, South Africa, Ocean Sci., 15, 1579–1592, https://doi.org/10.5194/os-15-1579-2019, 2019.
Jury, M. R.: Slowing of Caribbean through-flow, Deep Sea Res. Pt. 2, 180, 104682,
https://doi.org/10.1016/j.dsr2.2019.104682, 2020.
Jury, M. R. and Goschen, W. S.: Physical ocean-atmosphere variability over the shelf of South Africa from reanalysis products, Cont. Shelf Res., 202, 104135,
https://doi.org/10.1016/j.csr.2020.104135, 2020.
Jury, M. R., MacArthur, C., and Reason, C.: Observations of trapped waves in the atmosphere and ocean along the coast of southern Africa, S, Afr. Geogr. J., 72, 33–46, 1990.
Kennedy, A. D., Dong, X., Xi, B., Xie, S., Zhang, Y., and Chen, J.: A comparison of MERRA and NARR reanalyses with the DOE ARM SGP data, J. Climate, 24, 4541–4557, 2011.
Kruger, A. C. and Shongwe, S.: Temperature trends in South Africa: 1960–2003, Int. J. Climatol., 24, 1929–1945, 2004.
Kruger, A. C. and Nxumalo, M. P.: Historical rainfall trends in South Africa
1921–2015, Water SA, 43, 285–297, 2017.
Leber, G. M., Beal, L. M., and Elipot, S.: Wind and current forcing combine to drive strong upwelling in the Agulhas Current, J. Phys. Oceanogr., 47,
123–134, 2017.
Lee. H.-T., Gruber, A., Ellingson, R. G., and Laszlo, I.: Development of the HIRS outgoing longwave radiation climate dataset, J. Atmos. Ocean. Tech., 24, 2029–2047, 2007.
Lutjeharms, J. R. E.: The Agulhas Current, Springer, Berlin, 329 pp., 2006.
Lutjeharms, J. R. E., Cooper, J., and Roberts, M. J.: Upwelling at the inshore edge of the Agulhas Current, Cont. Shelf Res., 20, 737–761, 2000.
MacKeller, N., New, M., and Jack, C.: Observed and modelled trends in rainfall and temperature for South Africa 1960–2010, S. Afr. J. Science, 110, 1–13, 2014.
Malan, N., Backeberg, B., Biastoch, A., Durgadoo, J. V., Samuelsen, A.,
Reason, C., and Hermes, J.: Agulhas Current Meanders facilitate shelf-slope
exchange on the Eastern Agulhas Bank, J. Geophys. Res.-Oceans, 123,
4762–4778, 2018.
Malan, N. C., Durgadoo, J. V., Biastoch, A., Reason, C. J., and Hermes, J. C.: Multidecadal wind variability drives temperature shifts on the Agulhas Bank, J. Geophys. Res.-Oceans, 124, 3021–3035, 2019.
Mather, A. A., Garland, G. G., and Stretch, D. D.: Southern African sea levels: corrections, influences and trends, Afr. J. Marine Sci., 31, 145–156, 2009.
Morishima, W. and Akasaka, I.: Seasonal trends of rainfall and surface
temperature over Southern Africa, Afr. Study Monographs, 40, 67–76, 2010.
Morris, T., Hermes, J., Beal, L., du Plessis, M., Rae, C. D., Gulekana, M.,
Lamont, T., Speich, S., Roberts, M., and Ansorge, I. J.: The importance of
monitoring the Greater Agulhas Current and its inter-ocean exchanges using
large mooring arrays, S. Afr. J. Science, 113, 1–7, 2017.
Nkwinkwa, N., Rouault, M., and Johannessen, J. A.: Latent heat flux in the
Agulhas Current, Remote Sens.-Basel, 11, 1576, https://doi.org/10.3390/rs11131576, 2019.
Pattrick, P., Strydom, N. A., and Goschen, W. S.: Shallow-water, nearshore current dynamics in Algoa Bay, South Africa, with notes on the implications for larval fish dispersal, Afr. J. Marine Sci., 35, 269–282, 2013.
Philippon, N., Rouault, M., Richard, Y., and Favre, A.: The influence of ENSO on winter rainfall in South Africa, Int. J. Climatol., 32, 2333–2347, 2012.
Poli, P., Hersbach, H., Dee, D. P., Berrisford, P., Simmons, A. J., Vitart,
F., Laloyaux, P., Tan, D. G. H., Peubey, C., Thépaut, J.-N., Trémolet, Y., Hólm, E. V., Bonavita, M., Isaksen, L., and Fisher, M.: ERA-20C An atmospheric reanalysis of the Twentieth Century, J. Climate, 29, 4083–4097, 2016.
Reynolds, R. W., Smith, T. M., Liu, C., Chelton, D. B., Casey, K. S., and Schlax, M. G.: Daily high-resolution blended analyses for sea surface temperature, J. Climate, 20, 5473–5496, 2007.
Roberts, M. J.: Coastal currents and temperatures along the eastern region of
Algoa Bay, South Africa, with implications for transport and shelf-bay water
exchange, Afr. J. Marine Sci., 32, 145–161, 2010.
Rouault, M., Penven, P., and Pohl, B.: Warming in the Agulhas Current system
since the 1980s, Geophys. Res. Lett., 36, L12602, https://doi.org/10.1029/2009GL037987, 2009.
Rouault, M., Pohl, B., and Penven, P.: Coastal oceanic climate change and
variability from 1982 to 2009 around South Africa, Afr. J. Marine Sci., 32,
237–246, 2010.
Rouault, M. J. and Penven, P.: New perspectives on Natal Pulses from satellite observations, J. Geophys. Res.-Oceans, 116, 1–14, 2011.
Saha, S., Moorthi, S., Pan, H.-L., Wu, X., Wang, J., Nadiga, S., Tripp, P.,
Kistler, R., Woollen, J., Behringer, D., Liu, H., Stokes, D., Grumbine, R.,
Gayno, G., Wang, J., Hou, Y.-T., Chuang, H.-Y., Juang, H.-M., Sela, J.,
Iredell, M., Treadon, R., Kleist, D., van Delst, P., Keyser, D., Derber, J.,
Ek, M., Meng, J., Wei, H., Yang, R., Lord, S., van Den Dool, H., Kumar, A.,
Wang, W., Long, C., Chelliah, M., Xue, Y., Huang, B., Schemm, J.-K.,
Ebisuzaki, W., Lin, R., Xie, P.-P., Chen, M., Zhou, S., Higgins, W., Zou,
C.-Z., Liu, Q., Chen, Y., Han, Y., Cucurull, L., Reynolds, R. W., Rutledge,
G., and Goldberg, M.: The NCEP Coupled Forecast System reanalysis, B. Am.
Meteorol. Soc., 91, 1015–1057, 2010.
Scharler, U. M. and Baird, D.: The filtering capacity of selected Eastern Cape estuaries, South Africa, Water SA, 31, 483–490, 2005.
Schlegel, R. W. and Smit, A. J.: Climate change in coastal waters: time series properties affecting trend estimation, J. Climate, 29, 9113–9124, 2016.
Schumann, E. H.: Wind-driven mixed layer, coastal upwelling processes off the
south coast of South Africa, J. Marine Res., 57, 671–691, 1999.
Schumann, E. H. and Beekman, L. J.: Ocean temperature structures on the Agulhas Bank, T. Roy. Soc. S. Afr., 45, 191–203, 1984.
Schumann, E. H. and Brink, K. H.: Coastal trapped waves off the coast of South Africa: generation, propagation, current structures, J. Phys. Oceanogr., 20, 1206–1218, 1990.
Schumann, E. H. and Martin, J. A.: Climatological aspects of the coastal wind
field at Cape Town, Port Elizxabeth, Durban, S. Afr. Geogr. J., 73, 48–51,
1991.
Schumann, E. H. and Pearce, M. W.: Freshwater inflow, estuarine variability in the Gamtoos Estuary South Africa, Estuaries, 20, 124–133, 1997.
Schumann, E. H., Perrins, L.-A., and Hunter, I. T.: Upwelling along the south coast of the Cape Province South Africa, S. Afr. J. Science, 78, 238–242, 1982.
Swart, V. P. and Largier, J. L.: Thermal structure of Agulhas Bank water, S. Afr. J. Marine Sc., 5, 243–252, 1987.
Tadross, M., Jack, C., and Hewitson, B.: On RCM-based projections of change in southern African summer climate, Geophys. Res. Lett., 32, L23713,
https://doi.org/10.1029/2005GL024460, 2005.
Taylor, K. E., Stouffer, R. J., and Meehl, G. A.: An overview of CMIP5, the
experiment design, B. Am. Meteorol. Soc., 93, 485–498, 2012.
Tucker, C. J., Pinzon, J. E., Brown, M. E., Slayback, D. A., Pak, E. W., Mahoney, R., Vermote, E. F., and el Saleous, N.: An extended AVHRR 8 km NDVI dataset compatible with MODIS, SPOT vegetation data, Int. J. Remote Sens., 26, 4485–4498, 2005.
van Bladeren, D., Zawada, P. K., and Mahlangu, D.: Statistical based regional
flood frequency estimation study for South Africa using systematic,
historical, paleo-flood data, Water Res. Comm. Rep., 1260/1/70, Pretoria,
2007.
van Vuuren, D. P., Edmonds, J., Kainuma, M., Riahi, K., Thomson, A.,
Hibbard, K., Hurtt, G. C., Kram, T., Krey, V., Lamarque, J.-F., Masui, T.,
Meinshausen, M., Nakicenovic, N., Smith, S. J., and Rose, S. K.: The
representative concentration pathways: an overview, Climatic Change, 109,
5–31, 2011.
Yang, H., Lohmann, G., Wei, W., Dima, M., Ionita, M., and Liu, J.:
Intensification, poleward shift of subtropical western boundary currents in
a warming climate, J. Geophys. Res.-Oceans, 121, 4928–4945, 2016.
Short summary
The rate of change in the marine environment along the south coast of South Africa (32–37° S, 20–30° E) is studied using reanalysis observations for 1900–2015 and coupled ensemble model projections for 1980–2100. Although sea surface temperatures offshore are warming rapidly, a trend toward easterly winds and stronger shelf-edge currents have intensified nearshore upwelling (−0.03 °C yr−1) and contribute to a drier climate.
The rate of change in the marine environment along the south coast of South Africa (32–37° S,...