Satellite-derived Optical Absorption Properties in the New Zealand Sector of the Southern Ocean During Austral Summer of 2014

Abstract

The Southern Ocean contributes significantly to global primary production and satellite remote sensing provides several advantages in assessing primary production in the region. Both chlorophyll- and absorption-based primary production models have been used in many oceanic environments with absorption based models showing promising results to estimate primary production from remote sensing. To obtain a better understanding of the optical environment in the New Zealand sector of the Southern Ocean, optical absorption properties of dissolved and particulate organic matter along with phytoplankton chlorophyll and absorption properties were examined using both field and satellite-derived data. Satellite data from the Moderate resolution Imaging Spectroradiometer (MODIS) sensor and the quasi-analytical algorithm (QAA) were used to derive absorption products covering the same period as the R/V Araon transected the Southern Ocean from New Zealand to Terra Nova Bay in the Ross Sea during the 2014 Austral summer. Satellite SST and ocean color imagery revealed the presence of various water masses along the transect with a distinct band of elevated phytoplankton chlorophyll observed along the Polar Front. DOC concentrations were generally low with elevated values in the New Zealand shelf surface waters and a band of elevated DOC north of the Polar Front. CDOM absorption and spectral slope properties were also elevated in the northern section of the Southern Ocean. Satellite-derived particulate absorption at 443 nm generally revealed patterns similar to that of phytoplankton chlorophyll.