@article{fdi:010084301,
  title = {{R}emote analysis of the chlorophyll-a concentration using {S}entinel-2 {MSI} images in a semiarid environment in {N}ortheastern {B}razil},
  author = {{A}ranha, {T}. {R}. {B}. {T}. and {M}artinez, {J}ean-{M}ichel and {S}ouza, {E}. {P}. and {B}arros, {M}. {U}. {G}. and {M}artins, {E}. {S}. {P}. {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n this paper, the authors use remote-sensing images to monitor the water quality of reservoirs located in the semiarid region of {N}ortheast {B}razil. {S}entinel-2 {MSI} {TOA} {L}evel 1{C} reflectance images were used to remotely estimate the concentration of chlorophyll-a (chl-a), the main indicator of the trophic state of aquatic environments, in five reservoirs in the state of {C}eara, {B}razil. {A} three-spectral band retrieval model was calibrated using 171 water samples, collected from {N}ovember 2015 through {J}uly 2018 in 5 reservoirs. {F}or validation, 71 additional samples, collected from {A}ugust 2018 through {D}ecember 2019, were used to ensure a robust accuracy assessment. {T}he {TOA} {L}evel 1{C} products performed very well, achieving a relative {RMSE} of 28% and {R}-2 = 0.80. {D}ata on wind direction and speed, solar radiation and reservoir volume were used to generate a conceptual model to analyze the behavior of chl-a in the surface waters of the {C}astanhao reservoir. {D}uring 2019, the reservoir water quality showed strong variation, with concentration fluctuating from 30 to 95 mu g/{L} {W}e showed that the end of the dry season is marked by strong eutrophic conditions corresponding to very low water inflows into the reservoir. {D}uring the rainy season there is a large decrease in the chl-a concentration following the increase of the lake water storage. {D}uring the following dry season, satellite data show a progressive improvement of the trophic state controlled by wind intensity that promotes a better mixing of the reservoir waters and inhibiting the development of most phytoplankton.},
  keywords = {remote sensing ; water quality ; chlorophyll-a ; reservoirs ; semiarid ; {BRESIL} ; {ZONE} {SEMIARIDE} ; {CEARA} {ETAT}},
  booktitle = {},
  journal = {{W}ater},
  volume = {14},
  numero = {3},
  pages = {451 [22 p.]},
  year = {2022},
  DOI = {10.3390/w14030451},
  URL = {https://www.documentation.ird.fr/hor/fdi:010084301},
}