Analyse spatio-temporelle des patrons de chlorophylle dans la polynie NOW par télédétection du capteur SeaWiFS

Abstract

The North Water Polynya (NOW), in northern Baffin Bay, is one of the largest polynya in the Northern Hemisphere. As part of the International Arctic Polynya Program (IAPP), an International project (NOW project) took place from 1997 to 1999 to study this polynya using an ecosystemic approach. Sea viewing Wide Field-of-view Sensor (SeaWiFS) imagery of phytoplankton chlorophyll α pigment is presented for two summers (1998 and 1999). The precision of chlorophyll α estimations by SeaWiFS (41,3%) is slightly over the SeaWiFS team goal of 35%. However, eight of the 11 comparison points between in situ measurements of chlorophyll α and chlorophyll α estimated from SeaWiFS were underestimated by the algorithms. One explanation could be the pigment specific diffuse attenuation coefficient [K_d*(λ) m² mg^-1 Chl + phaeo] in the NOW polynya is significantly smaller, particularly in the blue region of the spectrum, than in the temperate regions. Despite these limitations related to high latitudes (low sun angle and phytoplankton communities adapted to polar conditions), the general patterns of the phytoplankton distribution obtained from SeaWiFS imagery and field measurements of chlorophyll α distribution in the polynya show similar trends."--Résumé abrégé par UMI