Three improved satellite chlorophyll algorithms for the Southern Ocean

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Johnson, R, Strutton, PG, Wright, SW, McMinn, A, Meiners, K
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell Publishing, Inc. 2013
• Subjects: Biological Sciences; Ecology; Marine and estuarine ecology (incl. marine ichthyology); Southern Ocean
• Online Access: https://doi.org/10.1002/jgrc.20270; http://ecite.utas.edu.au/86461

Remote sensing of Southern Ocean chlorophyll concentrations is the most effective wayto detect large-scale changes in phytoplankton biomass driven by seasonality and climatechange. However, the current algorithms for the Sea-viewing Wide Field-of-view Sensor(SeaWiFS, algorithm OC4v6), the Moderate Resolution Imaging Spectroradiometer(MODIS-Aqua, algorithm OC3M), and GlobColour significantly underestimate chlorophyllconcentrations at high latitudes. Here, we use a long-term data set from the Southern Ocean(20-160 degree E) to develop more accurate algorithms for all three of these products in southernhigh-latitude regions. These new algorithms improve in situ versus satellite chlorophyllcoefficients of determination (r2) from 0.27 to 0.46, 0.26 to 0.51, and 0.25 to 0.27, forOC4v6, OC3M, and GlobColour, respectively, while addressing the underestimationproblem. This study also revealed that pigment composition, which reflects speciescomposition and physiology, is key to understanding the reasons for satellite chlorophyllunderestimation in this region. These significantly improved algorithms will permit moreaccurate estimates of standing stocks and more sensitive detection of spatial and temporalchanges in those stocks, with consequences for derived products such as primary productionand carbon cycling.