@article{fdi:010073963,
  title = {{R}emote sensing of {T}richodesmium spp. mats in the western tropical {S}outh {P}acific},
  author = {{R}ousset, {G}. and {D}e {B}oissieu, {F}. and {M}enk{\`e}s, {C}hristophe and {L}efevre, {J}{\'e}r{\^o}me and {F}rouin, {R}. and {R}odier, {M}artine and {R}idoux, {V}. and {L}aran, {S}. and {B}onnet, {S}ophie and {D}upouy, {C}{\'e}cile},
  editor = {},
  language = {{ENG}},
  abstract = {{T}richodesmium is the major nitrogen-fixing species in the western tropical {S}outh {P}acific ({WTSP}) region, a hot spot of diazotrophy. {D}ue to the paucity of in situ observations, remote-sensing methods for detecting {T}richodesmium presence on a large scale have been investigated to assess the regional-to-global impact of this organism on primary production and carbon cycling. {A} number of algorithms have been developed to identify {T}richodesmium surface blooms from space, but determining with confidence their accuracy has been difficult, chiefly because of the scarcity of sea-truth information at the time of satellite overpass. {H}ere, we use a series of new cruises as well as airborne surveys over the {WTSP} to evaluate their ability to detect {T}richodesmium surface blooms in the satellite imagery. {T}he evaluation, performed on {MODIS} data at 250 m and 1 km resolution acquired over the region, shows limitations due to spatial resolution, clouds, and atmospheric correction. {A} new satellite-based algorithm is designed to alleviate some of these limitations, by exploiting optimally spectral features in the atmospherically corrected reflectance at 531, 645, 678, 748, and 869 nm. {T}his algorithm outperforms former ones near clouds, limiting false positive detection and allowing regional-scale automation. {C}ompared with observations, 80 % of the detected mats are within a 2 km range, demonstrating the good statistical skill of the new algorithm. {A}pplication to {MODIS} imagery acquired during the {F}ebruary-{M}arch 2015 {OUTPACE} campaign reveals the presence of surface blooms northwest and east of {N}ew {C}aledonia and near 20 degrees {S}-172 degrees {W} in qualitative agreement with measured nitrogen fixation rates. {I}mproving {T}richodesmium detection requires measuring ocean color at higher spectral and spatial (< 250 m) resolution than {MODIS}, taking into account environment properties (e.g., wind, sea surface temperature), fluorescence, and spatial structure of filaments, and a better understanding of {T}richodesmium dynamics, including aggregation processes to generate surface mats. {S}uch sub-mesoscale aggregation processes for {T}richodesmium are yet to be understood.},
  keywords = {{PACIFIQUE} {SUD} ; {ZONE} {TROPICALE} ; {NOUVELLE} {CALEDONIE}},
  booktitle = {},
  journal = {{B}iogeosciences},
  volume = {15},
  numero = {16},
  pages = {5203--5219},
  ISSN = {1726-4170},
  year = {2018},
  DOI = {10.5194/bg-15-5203-2018},
  URL = {https://www.documentation.ird.fr/hor/fdi:010073963},
}