Articles | Volume 15, issue 1
https://doi.org/10.5194/os-15-83-2019
© Author(s) 2019. 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-15-83-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
08 Feb 2019
Research article |
| 08 Feb 2019
| 08 Feb 2019
Frontogenesis of the Angola–Benguela Frontal Zone
Geophysical Institute, University of Bergen, Bjerknes Centre for
Climate Research, Bergen, Norway
Hervé Giordani
Centre National de Recherches
Météologiques, Météo-France, UMR-3589, Toulouse, France
Katerina Goubanova
Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile
CERFACS/CNRS, CECI UMR 531, Toulouse, France
Related authors
Shunya Koseki, Rubén Vázquez, William Cabos, Claudia Gutiérrez, Dmitry V. Sein, and Marie-Lou Bachèlery
Earth Syst. Dynam., 15, 1401–1416, https://doi.org/10.5194/esd-15-1401-2024, https://doi.org/10.5194/esd-15-1401-2024, 2024
Short summary
Short summary
Using a high-resolution regionally coupled model, we suggest that Dakar Niño variability will be reinforced under the Representative Concentration Pathway (RCP) 8.5 scenario. This may be induced by intensified surface heat flux anomalies and, secondarily, by anomalies in horizontal and vertical advection. Increased sea surface temperature (SST) variability can be associated with stronger wind variability, attributed to amplified surface temperature anomalies between ocean and land.
Shunya Koseki, Lander R. Crespo, Jerry Tjiputra, Filippa Fransner, Noel S. Keenlyside, and David Rivas
Biogeosciences, 21, 4149–4168, https://doi.org/10.5194/bg-21-4149-2024, https://doi.org/10.5194/bg-21-4149-2024, 2024
Short summary
Short summary
We investigated how the physical biases of an Earth system model influence the marine biogeochemical processes in the tropical Atlantic. With four different configurations of the model, we have shown that the versions with better SST reproduction tend to better represent the primary production and air–sea CO2 flux in terms of climatology, seasonal cycle, and response to climate variability.
Shunya Koseki, Priscilla A. Mooney, William Cabos, Miguel Ángel Gaertner, Alba de la Vara, and Juan Jesus González-Alemán
Nat. Hazards Earth Syst. Sci., 21, 53–71, https://doi.org/10.5194/nhess-21-53-2021, https://doi.org/10.5194/nhess-21-53-2021, 2021
Short summary
Short summary
This study investigated one case of a tropical-like cyclone over the Mediterranean Sea under present and future climate conditions with a regional climate model. A pseudo global warming (PGW) technique is employed to simulate the cyclone under future climate, and our simulation showed that the cyclone is moderately strengthened by warmer climate. Other PGW simulations where only ocean and atmosphere are warmed reveal the interesting results that both have counteracting effects on the cyclone.
Shunya Koseki and Priscilla A. Mooney
Hydrol. Earth Syst. Sci., 23, 2795–2812, https://doi.org/10.5194/hess-23-2795-2019, https://doi.org/10.5194/hess-23-2795-2019, 2019
Short summary
Short summary
This study revealed that Lake Malawi plays an important role for local precipitation in terms of spatial distribution and diurnal cycle in boreal summer (November to March). The diurnal cycle is detected by harmonics analysis and empirical orthogonal function analysis. An idealized simulation of WRF without Lake Malawi clearly showed that Lake Malawi is a source of local precipitation.
Shunya Koseki, Rubén Vázquez, William Cabos, Claudia Gutiérrez, Dmitry V. Sein, and Marie-Lou Bachèlery
Earth Syst. Dynam., 15, 1401–1416, https://doi.org/10.5194/esd-15-1401-2024, https://doi.org/10.5194/esd-15-1401-2024, 2024
Short summary
Short summary
Using a high-resolution regionally coupled model, we suggest that Dakar Niño variability will be reinforced under the Representative Concentration Pathway (RCP) 8.5 scenario. This may be induced by intensified surface heat flux anomalies and, secondarily, by anomalies in horizontal and vertical advection. Increased sea surface temperature (SST) variability can be associated with stronger wind variability, attributed to amplified surface temperature anomalies between ocean and land.
Shunya Koseki, Lander R. Crespo, Jerry Tjiputra, Filippa Fransner, Noel S. Keenlyside, and David Rivas
Biogeosciences, 21, 4149–4168, https://doi.org/10.5194/bg-21-4149-2024, https://doi.org/10.5194/bg-21-4149-2024, 2024
Short summary
Short summary
We investigated how the physical biases of an Earth system model influence the marine biogeochemical processes in the tropical Atlantic. With four different configurations of the model, we have shown that the versions with better SST reproduction tend to better represent the primary production and air–sea CO2 flux in terms of climatology, seasonal cycle, and response to climate variability.
Aurore Voldoire, Romain Roehrig, Hervé Giordani, Robin Waldman, Yunyan Zhang, Shaocheng Xie, and Marie-Nöelle Bouin
Geosci. Model Dev., 15, 3347–3370, https://doi.org/10.5194/gmd-15-3347-2022, https://doi.org/10.5194/gmd-15-3347-2022, 2022
Short summary
Short summary
A single-column version of the global climate model CNRM-CM6-1 has been designed to ease development and validation of the model physics at the air–sea interface in a simplified environment. This model is then used to assess the ability to represent the sea surface temperature diurnal cycle. We conclude that the sea surface temperature diurnal variability is reasonably well represented in CNRM-CM6-1 with a 1 h coupling time step and the upper-ocean model resolution of 1 m.
Florian Lemarié, Guillaume Samson, Jean-Luc Redelsperger, Hervé Giordani, Théo Brivoal, and Gurvan Madec
Geosci. Model Dev., 14, 543–572, https://doi.org/10.5194/gmd-14-543-2021, https://doi.org/10.5194/gmd-14-543-2021, 2021
Short summary
Short summary
A simplified model of the atmospheric boundary layer (ABL) of intermediate complexity between a bulk parameterization and a full three-dimensional atmospheric model has been developed and integrated to the NEMO ocean model.
An objective in the derivation of such a simplified model is to reach an apt representation of ocean-only numerical simulations of some of the key processes associated with air–sea interactions at the characteristic scales of the oceanic mesoscale.
Shunya Koseki, Priscilla A. Mooney, William Cabos, Miguel Ángel Gaertner, Alba de la Vara, and Juan Jesus González-Alemán
Nat. Hazards Earth Syst. Sci., 21, 53–71, https://doi.org/10.5194/nhess-21-53-2021, https://doi.org/10.5194/nhess-21-53-2021, 2021
Short summary
Short summary
This study investigated one case of a tropical-like cyclone over the Mediterranean Sea under present and future climate conditions with a regional climate model. A pseudo global warming (PGW) technique is employed to simulate the cyclone under future climate, and our simulation showed that the cyclone is moderately strengthened by warmer climate. Other PGW simulations where only ocean and atmosphere are warmed reveal the interesting results that both have counteracting effects on the cyclone.
Théo Brivoal, Guillaume Samson, Hervé Giordani, Romain Bourdallé-Badie, Florian Lemarié, and Gurvan Madec
Ocean Sci. Discuss., https://doi.org/10.5194/os-2020-78, https://doi.org/10.5194/os-2020-78, 2020
Preprint withdrawn
Short summary
Short summary
We investigate the interactions between near-surface winds and oceanic surface currents on the north-east atlantic region using a simplified lower atmosphere model coupled with an ocean model. we show that the upper ocean kinetic energy is significantly reduced due to these interactions, but in a smaller amplitude than if the wind feedback is ignored. We also show that wind-current interactions affect the deeper ocean by modifying its vertical structure and consequently the pressure field.
Shunya Koseki and Priscilla A. Mooney
Hydrol. Earth Syst. Sci., 23, 2795–2812, https://doi.org/10.5194/hess-23-2795-2019, https://doi.org/10.5194/hess-23-2795-2019, 2019
Short summary
Short summary
This study revealed that Lake Malawi plays an important role for local precipitation in terms of spatial distribution and diurnal cycle in boreal summer (November to March). The diurnal cycle is detected by harmonics analysis and empirical orthogonal function analysis. An idealized simulation of WRF without Lake Malawi clearly showed that Lake Malawi is a source of local precipitation.
Aurore Voldoire, Bertrand Decharme, Joris Pianezze, Cindy Lebeaupin Brossier, Florence Sevault, Léo Seyfried, Valérie Garnier, Soline Bielli, Sophie Valcke, Antoinette Alias, Mickael Accensi, Fabrice Ardhuin, Marie-Noëlle Bouin, Véronique Ducrocq, Stéphanie Faroux, Hervé Giordani, Fabien Léger, Patrick Marsaleix, Romain Rainaud, Jean-Luc Redelsperger, Evelyne Richard, and Sébastien Riette
Geosci. Model Dev., 10, 4207–4227, https://doi.org/10.5194/gmd-10-4207-2017, https://doi.org/10.5194/gmd-10-4207-2017, 2017
Short summary
Short summary
This study presents the principles of the new coupling interface based on the SURFEX multi-surface model and the OASIS3-MCT coupler. As SURFEX can be plugged into several atmospheric models, it can be used in a wide range of applications. The objective of this development is to build and share a common structure for the atmosphere–surface coupling of all these applications, involving on the one hand atmospheric models and on the other hand ocean, ice, hydrology, and wave models.
V. Masson, P. Le Moigne, E. Martin, S. Faroux, A. Alias, R. Alkama, S. Belamari, A. Barbu, A. Boone, F. Bouyssel, P. Brousseau, E. Brun, J.-C. Calvet, D. Carrer, B. Decharme, C. Delire, S. Donier, K. Essaouini, A.-L. Gibelin, H. Giordani, F. Habets, M. Jidane, G. Kerdraon, E. Kourzeneva, M. Lafaysse, S. Lafont, C. Lebeaupin Brossier, A. Lemonsu, J.-F. Mahfouf, P. Marguinaud, M. Mokhtari, S. Morin, G. Pigeon, R. Salgado, Y. Seity, F. Taillefer, G. Tanguy, P. Tulet, B. Vincendon, V. Vionnet, and A. Voldoire
Geosci. Model Dev., 6, 929–960, https://doi.org/10.5194/gmd-6-929-2013, https://doi.org/10.5194/gmd-6-929-2013, 2013
Cited articles
Astudillo, O., Dewitte, B., Mallet, M., Frappart, F., Rutllant, J. A., Ramos,
M., Bravo, L., Goubanova, K., and Illig, S.: Surface winds off Peru-Chile:
Observing closer to the coast from radar altimetry, Remote Sens. Environ.,
191, 179–196, https://doi.org/10.1016/j.rse.2017.01.010, 2017.
Auel, H. and Verheye, H. M.: Hypoxia tolerance in the copepod Calanoides
carinatus and the effect of an intermediate oxygen minimum layer on copecod
vertical distribution in the northern Bengulea Current upwelling system and
the
Angola-Benguela Front, J. Exp. Mar. Biol. Ecol., 352, 234–243,
2007.
Chavez, F. P. and Messié, M.: A comparison of eastern boundary
upwelling
ecosystem, Prog. Oceanogr., 83, 80–96, 2009.
Chen, Z., Yan, X.-H., Jp, Y.-H., Jiang, L., and Jiang, Y.: A study of
Bengulea upwelling system using different upwelling indices derived from
remotely sensed data, Cont. Shelf Res., 45, 27–33, 2012.
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.
Colberg, F. and Reason, C. J. C.: A model investigation of internal
variability in
the Angola Benguela Forntal Zone, J. Geophys. Res., 112, C07008,
https://doi.org/10.1029/2006JC003920, 2007.
Dinniman, M. S. and Rienecker, M. M.: Frontogenesis in the North Pacific
Ocean
Frontal Zones-A Numerical Simulation, J. Phys. Oceanogr., 29, 537–559, 1999.
Doi, T., Tozuka, T., Sasaki, H., Masumoto, Y., and Yamagata, T.: Seasonal
and
interannual variations of oceanic conditions in the Angola Dome,
J. Phys. Oceanogr., 37, 2698–2713, https://doi.org/10.1175/2007JPO3552.1, 2007.
Fennel, W., Junker, T., Schmidt, M., and Mohrholz, V.: Response of the
Benguela
upwelling system to spatial variations in the wind stress, Cont. Shelf Res., 45, 65–77,
2012.
Florenchie, P., Lutjeharms, J. E., Reason, C. J. C., Masson, S., and Rouault,
M.: The source of Benguela Ninos in the South Atlantic Ocean, Geophys. Res.
Lett., 30, 1505, https://doi.org/10.1029/2003GL017172, 2003.
Gammelsrød, T., Bartholomae, C. H., Boyer, D. C., Filipe, V. L. L., and
O'Toole, M. J.:
Intrusion of warm surface water along the Angolan-Namibian coast in
February–March 1995: the 1995 Benguela Nino,
S. Afr. J. Marine Sci.,
19, 41–56, https://doi.org/10.2989/025776198784126719, 1998.
Giordani, H. and Caniaux, G.: Sensitivity of cyclogenesis to sea surface
temperature in
the Northwestern Atlantic, Mon. Weather Rev., 129, 1273–1295, 2001.
Giordani, H. and Caniaux, G.: Diagnosing vertical motion in the Equatorial
Atlanitc, Ocean Dynam., 61, 1995–2018, https://doi.org/10.1007/s10236-01-0467-7,
2011.
Giordani, H., Caniaux, G., and Voldoire, A.: Intraseasonal mixed-layer heat
budget in the equatorial Atlantic during the cold tongue development 2006,
J. Geophys. Res., 118, 650–671, https://doi.org/10.1029/2012JC008280, 2013.
Giordani, H. and Caniaux, G.: Lagrangian sources of frontogenesis in the
equatorial Atlantic front, Clim. Dynam., 43, 3147–3162,
https://doi.org/10.1007/s00382-014-2293-3, 2014.
Goubanova, K., Illig, S., Machu, E., Garcon, V., and Dewitte, B.: SST
subseasonal
variability in the central Benguela upwelling system as inferred from
satellite
observation (1999–2009), J. Geophys. Res., 118, 4092–4110,
https://doi.org/10.1002/jgrc.20287, 2013.
Goubanova, K., Sanchez, G., E., Frauen, C., and Voldoire A.: Role of remote
and local wind stress forcing in the development of the warm SST errors in
the southeastern tropical Atlantic in a coupled high-resolution model, Clim.
Dynam., 2018.
Griffies, S. M., Harrison, M. J., Pacanowski, R. C., and Rosati, A.:
Technical guide to MOM4, GFDL Ocean Group Technical Report No. 5, 337 pp.,
available at: https://www.gfdl.noaa.gov/-fms (last access:
15 November 2018), 2004.
Hanshingo, K. and Reason, C. J. C.: Modelling the atmospheric response over
southern Africa to SST forcing in the southeast tropical Atlantic and
southwest subtropical Indian Oceans, Int. J. Climatol., 29, 1001–1012,
https://doi.org/10.1002/joc.1919, 2009.
Hastenrath, S. and Lamb, P.: On the dynamics and climatology of surface flow
over the
equatorial oceans, Tellus, 30, 436–448, 1978.
Hirst, A. C. and Hastenrath, S.: Atmopshere-Ocean Mechanisms of Climate
Anomalies in the Angola-Tropical Atlantic Sector, J. Phys. Oceanogr., 13,
1146–1157, https://doi.org/10.1175/1520-0485(1983)013<1146:AOMOCA>2.0.CO;2, 1983.
Junker, T., Schmidt, M., and Mohrholz, V.: The relation of wind stress curl
and
meridional transport in the Benguela upwelling system, J. Mar. Res., 143, 1–6,
2015.
Junker, T., Mohrholz, V., Siegfired, L., and van der Plas, A.: Seasonal to
interannual
variability of water mass characteristics and current on the Namibian shelf,
J. Mar. Syst., 165, 36–46, 2017.
Kay, E., Eggert, A., Flohr, A., Lahajnar N., Nausch, G., Nuemann, A., Rixen,
T., Schmidt, M.,
Van der Pla, A., and Wasmund, N.: Biogeochemical processes and
turnover
rates in the Northern Benguela Upwelling System, J. Mar. Syst., 188, 63–80,
2018.
Kazmin, A. S. and Rienecker, M. M.: Variability and forntogenesis in the
large-scale
oceanic frontal zones, J. Geophys. Res., 101, 907–921, 1996.
Keyser, D., Reeder, M. J., and Reed, R. J.: A Generalization of
Petterssens's
Frontogenesis Function and Its Relation to the Forcing of Vertical Motion,
Mon. Weather Rev., 116, 762–780, 1988.
Klein S. A. and Hartmann, D. L.: The Seasonal Cycle of Low Stratiform
Clouds,
J. Clim., 6, 1587–1606, 1993.
Koseki, S., Keenlyside, N., Demissie, T., Toniazzo, T., Counillon, F.,
Bethke, I., Ilicak, M.,
and Shen, M.-L.: Causes of the large warm SST bias in the Angola-Benguela
Frontal
Zone in the Norwegian Earth System Model, Clim. Dynam., 50, 4651–4670,
https://doi.org/10.1007/s00382-017-3896-2, 2018.
Kopte, R., Brandt, P., Dengler, M., Tchipalanga, P. C. M., Macueria, M., and
Ostrowski, M.: The Angola Current: Flow and hydrographic characteristic as observed at
11∘ S,
J. Geophys. Res.-Oceans, 122, 1177–1189, https://doi.org/10.1002/2016JC012374, 2017.
Lutz, K., Jacobeit, J., and Rathmann, J.: Atlantic warm and cold water
events and
impact on African west coast precipitation, Int. J. Climatol., 35, 128–141,
2015.
Manhique, A. J., Reason, C. J. C., Silinto, B., Zucula, J., Raiva, I.,
Congolo, F., and
Mavume, A. F.: Extreme rainfall and floods in southern Africa in January
2013 and
associated circulation patterns, Nat. Hazards, 77, 679–691,
https://doi.org/10.1007/s11069-015-1616-y, 2015.
Mazeika, P. A.: Thermal domes in the eastern tropical Atlantic Ocean,
Limnol.
Oceanogr., 12, 537–539, 1967.
Mohrholz, V., Schmidt, M., Lutjeharms, J. R. E., and John, H.-C. H.:
Space-time behavior of the Angola-Benguela Frontal Zone during the Benguela
Nino of April 1999, Int. J. Remote Sens., 25, 1400,
https://doi.org/10.1080/01431160310001592265, 2004.
Moisan, J. R. and Niler, P. P.: The Seasonal Heat Budget of the North
Pacific: Net Heat Flux and Heat Storage Rate (1950–1990), J. Phys.
Oceanogr., 28, 401–421, 1998.
NCAR/UCAR Climate Data Guide: Climate Forecast System Reanalysis (CFSR),
available at:
https://climatedataguide.ucar.edu/climate-data/climate-forecast-system-reanalysis-cfsr,
last access: 7 February 2019.
NOAA: Optimum Interpolation Sea Surface Temperature (OISST), available at:
https://www.ncdc.noaa.gov/oisst, last access: 7 February 2019.
Pfeifroth, U., Hollmann, R., and Ahrens, B.: Cloud Cover Diurnal Cycles in
Satellite
Data and Regional Climate Model Simulations,
Meteorologische Z., 21, 551–560, 2012.
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. Clim., 20, 5473–5496, 2007.
Rouault, M., Florenchie, P., Fauchereau, N., and Reason, C. J. C.: South
east
tropical Atlantic warm events and southern African rainfall,
Geophys. Res. Lett., 30, 8009, https://doi.org/10.1029/2002GL014840, 2003.
Rouault, M.: Bi-annual intrusion of tropical water in the northern Benguela
upwelling,
Geophys. Res. Lett., 39, L12606, https://doi.org/10.1029/2012GL052099, 2012.
Rouault, M., Illig, S., Lübbecke, J., and Koungue, R. A. I.: Origin,
development and demise of the 2010–2011 Benguela Niño, J. Mar. Syst.,
188, 39–48, https://doi.org/10.1016/j,jmarsys.2017.07.007, 2018.
Saha, S., Moorti 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., Juang, H.-M. H., 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., 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 Climate Forecast System Reanalysis, B. Am. Meteorol.
Soc., 91, 1015–1058, https://doi.org/10.1175/2010BAMS3001.1, 2010.
Santos, F., Gomez-Gesteria, M., deCastro, M., and Alvarez, I.: Differences in
coastal and oceanic SST trends due to the strengthening of coastal upwelling
along the Benguela current system, Cont. Shelf Res., 34, 79–86, 2012.
Tozuka, T. and Cronin, M. G.: Role of mixed layer depth in surface
frontogenesis: The Agulhas Return Current front, Geophys. Res. Lett., 41,
2447–2453, https://doi.org/10.1002/2014GL059624, 2014
Tozuka, T., Ohishi, S., and Cronin, M. G.: A metric for surface heat flux
effect on
horizontal sea surface temperature gradients, Clim. Dynam., 51, 547–561,
https://doi.org/10.1007/s00382-017-3940-2, 2018.
Veitch, J. A., Florenchie, P., and Shillington, F. A.: Seasonal and
interannual fluctuations of the Angola-Benguela Frontal Zone (ABFZ) using
4.5 km resolution satellite imagery from 1982 to 1999, Int. J.
Remote Sens., 27, 987–998, https://doi.org/10.1080/01431160500127914, 2006.
Vizy, E. K., Cook, K. H., and Sun, X.: Decadal change of the south Atlantic
ocean Angola-Benguela forntal zone since 1980, Clim. Dynam., 51, 3251–3273,
https://doi.org/10.1007/s00382-018-4077-7, 2018.
Xu Z., Chang, P., Richter, I., Kim, W., and Tang, G.: Diagnosing southeast
tropical
Atlantic SST and ocean circulation biases in the CMIP5 ensemble, Clim. Dynam., 43,
3123–3145, https://doi.org/10.1007/s00382-014-2247-9, 2014.
Zuidema, P. et al.: Challenges and Prospects for Reducing Coupled Climate
Model SST Biases in the Eastern Tropical Atlantic and Pacific Oceans: The US
CLIVAR Eastern Tropical Oceans Synthesis Working Group, B. Amer. Meteorol.
Soc., 97, 2305–2328, https://doi.org/10.1175/BAMS-D-15-00274.1, 2016.
Short summary
With an ocean frontogenetic function, the frontogenesis of the Angola–Benguela Frontal Zone (ABFZ) is investigated. On an annual-mean timescale, the meridional confluence of Angola and Benguela currents and tilting effect due to the upwelling are the main sources to generate the ABFZ. The annual cycle of the ABFZ is also mainly driven by these two effects.
With an ocean frontogenetic function, the frontogenesis of the Angola–Benguela Frontal Zone...
