Evaluation of ocean color algorithms in the southeastern Beaufort Sea, Canadian Arctic: New parameterization using SeaWiFS

• Main Authors: Meris Spectral B, Sélima Ben Mustapha, Pierre Larouche
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Arctic Ocean; Arctique*; Beaufort Sea; Climate change; Phytoplankton
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.666.8022; http://aquatel.uqar.ca/Publi/BenMustapha_etal_CJRS_2012.pdf

Abstract. With the increasing interest for Arctic Ocean resources and faced with its sensitivity to climate change, it is important to accurately monitor the chlorophyll-a (Chla) concentration that is a key indicator of phytoplankton biomass and marine productivity. The performances of three operational algorithms (OC4v6, OC3Mv6, OC4Mev6), two Arctic adapted algorithms (OC4L, OC4P), and one semi-analytical (GSM01) algorithm to estimate Chla were evaluated using in situ measurements collected in the southeastern Beaufort Sea. All evaluated algorithms clearly overestimated Chla by a factor of three to five. A high contribution of colored dissolved organic matter and nonalgal particles to the blue light absorption appeared as the source of that poor performance. It was also found that fluorometrically measured Chla were two times greater than those determined from high-performance liquid chromatography, contributing to the observed discrepancies between our findings and previous studies carried out in the Arctic. We propose regionally adapted and new algorithms allowing accurate estimation of Chla in the southeastern Beaufort Sea. Finally, a matchup analysis of coincident in situ data and satellite overpass showed that the normalized water-leaving reflectance and the blue-to-green ratio retrieval were more accurate for SeaWiFS than for MODIS and MERIS. Résumé. Avec l’intérêt croissant pour les ressources de l’océan Arctique et face a ̀ sa sensibilite ́ aux changements climatiques, il est important de suivre de façon précise la concentration de la chlorophylle-a (Chla) qui est un indicateur cle ́ de la biomasse phytoplanctonique et de la productivite ́ marine. La performance de trois algorithmes opérationnels