Use of bio-optical profiling float data in validation of ocean colour satellite products in a remote ocean region

Bożena Wojtasiewicz, Nick J. Hardman-Mountford, David Antoine, François Dufois, Dirk Slawinski, Thomas W. Trull

    Research output: Contribution to journalArticle

    8 Citations (Scopus)

    Abstract

    Utility of data from autonomous profiling floats for the validation of satellite ocean colour products from current satellite ocean colour sensors was assessed using radiometric and chlorophyll a fluorescence data from biogeochemical profiling floats (BGC-Argo) deployed in the subtropical gyre of the Indian Ocean. One of the floats was equipped with downward irradiance and upwelling radiance sensors, allowing the remote sensing reflectance, Rrs, to be determined. Comparisons between satellite and in situ Rrs indicated good agreement for the shorter wavelengths, but weak relationships for both satellites for the 555 nm channel, and showed that radiometers deployed on multipurpose, off-the-shelf BGC-Argo floats can provide validation-quality measurements. About 300 chlorophyll a concentration match-ups were achieved within 18 months, which increased the number of validation data points available for the Indian Ocean as a whole by a factor of ~4 from the previous historical record. Generally, the satellite data agreed with the float-derived chlorophyll concentration within the uncertainty of ±35%, for the band-difference (OCI) and band-ratio (OC3) algorithms, but not for a semianalytical ocean colour model (GSM) that exhibited significantly higher chlorophyll values (>100% mean difference). Our results indicate that autonomous float-based measurements provide substantial potential for improving regional validation of satellite ocean colour products in remote areas.

    Original languageEnglish
    Pages (from-to)275-290
    Number of pages16
    JournalRemote Sensing of Environment
    Volume209
    DOIs
    Publication statusPublished - 1 May 2018

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