Inter-comparison of OC-CCI chlorophyll-a estimates with precursor datasets

Ocean colour is the only essential climate variable that targets a biological variable (chlorophyll concentration, Chl) and is also amenable to remote sensing at the global scale. However, the finite lifetime of individual ocean-colour sensors, and the differ-ences in their characteristics increase the difficulty of creating a long-term, consistent, ocean-colour time series that meets the requirements of climate studies. The Ocean Colour Climate Change Initiative (OC-CCI), a European Space Agency pro-gramme, has recently produced a time series of satellite-based ocean-colour products at the global scale, merging data from three sensors: SeaWiFS, MODIS-Aqua and MERIS, while attempting to reduce inter-sensor biases. In this work we present a comparison between the OC-CCI chlo-rophyll-a product and precursor satellite-derived datasets, from both, single missions (SeaWiFS, MODIS-Aqua and MERIS) and multi-mission products (GlobColour, and MEaSUREs). To this end, OC-CCI global monthly composites are compared to the similar products offered by single-mission and multi-mission records. Our results indicate that the OC-CCI product provides a higher number of observations. Comparing the observations that match with precursors the OCCCI product was generally most similar to the single-mission products. Relationships between OC-CCI and other precursors did not change significantly during a common and continuous period, and, on average the root-mean-square differences between log-transformed chlorophyll-a con-centration are below or equal to 0.11. Further, when considering variability that could arise when merging data from different sources, it is shown that the OC-CCI product is more long-term constant than other multi-mission initiatives studied here.

COUTO Andre Belo;  BROTAS Vanda;  MELIN Frederic;  GROOM Steve;  SATHYENDRANATH Shubha; 

2016-10-04

TAYLOR & FRANCIS LTD

JRC101412

0143-1161,   

http://www.tandfonline.com/doi/full/10.1080/01431161.2016.1209313,    https://publications.jrc.ec.europa.eu/repository/handle/JRC101412,   

10.1080/01431161.2016.1209313,