@article{fdi:010096406,
  title = {{M}echanisms driving mesoscale latent heat flux variations and mixed layer heat content evaluation in the {N}orthwest {T}ropical {A}tlantic},
  author = {{F}ernández, {P}. and {S}peich, {S}. and {L}apeyre, {G}. and {P}asquero, {C}. and {C}onejero, {C}. and {R}enault, {L}ionel and {D}esbiolles, {F}abien},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n this study, a high-resolution ocean-atmosphere coupled simulation is used to assess the effects of sea surface temperature ({SST}), surface currents, and ocean vertical stratification on the spatial variability of latent heat flux ({LHF}) and the stability of the marine atmospheric boundary layer ({MABL}) in the {N}orthwest {T}ropical {A}tlantic during {J}anuary and {F}ebruary 2020. {T}he analysis focuses on the ocean mesoscale ({O}(50-250 km)) across the {N}orthwest {T}ropical {A}tlantic (referred to as the {EURECA} region in this study) and within three sub-regions characterized by different ocean dynamical regimes: {A}mazon, {D}ownstream, and {T}radewind. {R}esults indicate that the coupling between {SST} and wind speed (and specific humidity) is stronger (weaker) in the {A}mazon and {D}ownstream regions, influenced by the warm coastal {N}orth {B}razil {C}urrent eddy corridor and the {A}mazon {R}iver plume, than in the {T}radewind region, representative of the open ocean, consistent with previous remote sensing studies. {O}verall, warmer {SST}s are associated with increased wind speeds and variations in specific humidity, deviating from {C}lausius-{C}lapeyron expectations. {W}e interpret this as the result of active ocean processes modifying the near-surface atmosphere, enhancing vertical motion in the {MABL}, and transporting momentum and drier air from the free troposphere toward the surface. {T}o further investigate the impact of mesoscale {SST} features on {LHF}, we apply a linear, {SST}-based downscaling method. {R}esults show that these mesoscale {SST} structures induce a substantial increase in {LHF}, 46.8 {W}m-2{K}-1 on average in the {A}mazon and {D}ownstream regions (warm eddy corridor). {I}n the {T}radewind region, the {LHF} sensitivity to {SST} is smaller, at about 35 {W}m-2{K}-1. {F}or the {A}mazon region, of the 46.7 {W}m-2{K}-1 change in {LHF} associated with {SST}, approximately 7.8 {W}m-2{K}-1 is attributed to direct mesoscale {SST} changes (thermodynamic contribution), while the remainder is linked to mesoscale {SST}-induced modifications in near-surface atmospheric circulation (dynamic contribution), mainly due to the mesoscale {SST}-induced humidity undersaturation imbalances. {T}he influence of surface currents on {LHF} is weaker, with deviations not exceeding 15 {W}m-2. {F}inally, we focus on the {SST} mesoscale anomalies linked to the {A}mazon freshwater plume. {W}e find them to be persistent throughout the period of study affecting {LHF} by the mechanisms described above. {L}ateral advection and heat loss to the atmosphere tend to dilute them with their environment by the end of the period of study. {T}his work underscores the importance of a regionalized approach to mesoscale air-sea interaction studies in the {N}orthwest {T}ropical {A}tlantic, as {LHF} sensitivity to {SST} and surface currents exhibits strong spatial variability driven by distinct oceanic dynamics. {S}ubmesoscale {LHF} sensitivity to {SST} and currents is not addressed here and will be the subject of future research.},
  keywords = {{ATLANTIQUE} ; {ZONE} {TROPICALE} ; {ATLANTIQUE} {NORD} {OUEST}},
  booktitle = {},
  journal = {{O}cean {S}cience},
  volume = {22},
  numero = {1},
  pages = {699--725},
  ISSN = {1812-0784},
  year = {2026},
  DOI = {10.5194/os-22-699-2026},
  URL = {https://www.documentation.ird.fr/hor/fdi:010096406},
}