@article{fdi:010075673,
  title = {{L}agrangian pathways in the southern {B}enguela upwelling system},
  author = {{R}agoasha, {N}. and {H}erbette, {S}teven and {C}ambon, {G}ildas and {V}eitch, {J}. and {R}eason, {C}. and {R}oy, {C}laude},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he effect of ocean currents on fish eggs and larvae during their journey from spawning to nursery grounds in the {S}outhern {B}enguela upwelling system is poorly understood. {T}he survival and successful transport of fish eggs and larvae results from complex biological and physical processes. {T}his study focuses on the advective processes, more specifically on how the dynamics and characteristics of the ocean currents shape the {L}agrangian pathways in the {S}outhern {B}enguela. {A} mesoscale eddy resolving interannual (1989-2010) simulation of the region, with a horizontal resolution of 7.5 km, is used to study processes impacting the connectivity between the western edge of the {A}gulhas {B}ank and the west coast upwelling region. {A} set of {L}agrangian experiments are conducted with particles being released within the top 100 m of the water column along an across-shore transect off {C}ape {P}oint (34 degrees {S}). {T}ransport success is given by the ratio of the number of particles that reach {S}t {H}elena {B}ay (32 degrees {S}) over the total number of particles released. {T}he model results show a strong seasonal cycle in transport success which is governed by the complex three-dimensional structure of the along-shore jets, their variability, together with the wind-induced {E}kman drift. {T}ransport success is most efficient in spring when the {B}enguela {J}et consists of one coherent intensified single-core branch that flows over the 300 m isobath, and when wind-induced {E}kman transport favours the retention of particles within the jet. {A}t this time of the year, the pathway leading to successful transport is located inshore, with 90% of particles released inshore the 300 m isobath being successfully transported to {S}t {H}elena {B}ay in < 15 days. {T}his pathway is also characterized by low eddy kinetic energy values. {D}uring the upwelling season ({D}ecember {M}arch), transport success becomes less efficient, and less sensitive to the initial across-shore position of the particles. {T}he inshore route no longer dominates, as the majority of particles follow offshore pathways. {T}he {B}enguela {J}et shifts offshore and splits into several branches due to the shoaling of the poleward undercurrent. {T}he entrainment of particles within the offshore branch of the jet is favored by the dominating offshore wind-induced {E}kman transport. {P}articles trapped in the offshore branch get exposed to higher mesoscale variability. {T}heir northward progression is slower, which leads to journeys generally exceeding 20 days. {T}his study shows that successful transport from the {A}gulhas {B}ank to the west coast upwelling region cannot be attributed to only a simple wind induced modulation of the jet. {I}t explores how the seasonal modulation of the {B}enguela {J}et, poleward undercurrent and offshore {E}kman transport combine together with the turbulent off shelf eddy field to set-up the characteristics of transport success.},
  keywords = {{B}enguela ; {U}pwelling ; {A}longshore connectivity ; {L}agrangian pathways ; {C}oastal jet ; {P}oleward undercurrent ; {ATLANTIQUE} ; {BENGUELA}},
  booktitle = {},
  journal = {{J}ournal of {M}arine {S}ystems},
  volume = {195},
  numero = {},
  pages = {50--66},
  ISSN = {0924-7963},
  year = {2019},
  DOI = {10.1016/j.jmarsys.2019.03.008},
  URL = {https://www.documentation.ird.fr/hor/fdi:010075673},
}