@article{fdi:010085305,
  title = {{W}intertime process study of the {N}orth {B}razil current rings reveals the region as a larger sink for {CO}2 than expected},
  author = {{O}livier, {L}. and {B}outin, {J}. and {R}everdin, {G}. and {L}ef{\`e}vre, {N}athalie and {L}andschutzer, {P}. and {S}peich, {S}. and {K}arstensen, {J}. and {L}abaste, {M}. and {N}oisel, {C}. and {R}itschel, {M}. and {S}teinhoff, {T}. and {W}anninkhof, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he key processes driving the air-sea {CO}2 fluxes in the western tropical {A}tlantic ({WTA}) in winter are poorly known. {WTA} is a highly dynamic oceanic region, expected to have a dominant role in the variability in {CO}2 air-sea fluxes. {I}n early 2020 ({F}ebruary), this region was the site of a large in situ survey and studied in wider context through satellite measurements. {T}he {N}orth {B}razil {C}urrent ({NBC}) flows northward along the coast of {S}outh {A}merica, retroflects close to 8 degrees {N} and pinches off the world's largest eddies, the {NBC} rings. {T}he rings are formed to the north of the {A}mazon {R}iver mouth when freshwater discharge is still significant in winter (a time period of relatively low run-off). {W}e show that in {F}ebruary 2020, the region (5-16 degrees {N}, 50-59 degrees {W}) is a {CO}2 sink from the atmosphere to the ocean (-1.7 {T}g{C} per month), a factor of 10 greater than previously estimated. {T}he spatial distribution of {CO}2 fugacity is strongly influenced by eddies south of 12 degrees {N}. {D}uring the campaign, a nutrient-rich freshwater plume from the {A}mazon {R}iver is entrained by a ring from the shelf up to 12 degrees {N} leading to high phytoplankton concentration and significant carbon drawdown (similar to 20 % of the total sink). {I}n trapping equatorial waters, {NBC} rings are a small source of {CO}2. {T}he less variable {N}orth {A}tlantic subtropical water extends from 12 degrees {N} northward and represents similar to 60 % of the total sink due to the lower temperature associated with winter cooling and strong winds. {O}ur results, in identifying the key processes influencing the air-sea {CO}2 flux in the {WTA}, highlight the role of eddy interactions with the {A}mazon {R}iver plume. {I}t sheds light on how a lack of data impeded a correct assessment of the flux in the past, as well as on the necessity of taking into account features at mesoand small scales.},
  keywords = {{ATLANTIQUE} ; {AMAZONIE} ; {ZONE} {TROPICALE} ; {BRESIL} {COURANT} {NORD}},
  booktitle = {},
  journal = {{B}iogeosciences},
  volume = {19},
  numero = {12},
  pages = {2969--2988},
  ISSN = {1726-4170},
  year = {2022},
  DOI = {10.5194/bg-19-2969-2022},
  URL = {https://www.documentation.ird.fr/hor/fdi:010085305},
}