Retrieval of Particulate Backscattering Using Field and Satellite Radiometry: Assessment of the QAA Algorithm

oleh: Jaime Pitarch, Marco Bellacicco, Emanuele Organelli, Gianluca Volpe, Simone Colella, Vincenzo Vellucci, Salvatore Marullo

Format: Article
Diterbitkan: MDPI AG 2019-12-01

Deskripsi

Particulate optical backscattering (b<sub>bp</sub>) is a crucial parameter for the study of ocean biology and oceanic carbon estimations. In this work, b<sub>bp</sub> retrieval, by the quasi-analytical algorithm (QAA), is assessed using a large in situ database of matched b<sub>bp</sub> and remote-sensing reflectance (R<sub>rs</sub>). The QAA is also applied to satellite R<sub>rs</sub> (ESA OC-CCI project) as well, after their validation against in situ R<sub>rs</sub>. Additionally, the effect of Raman Scattering on QAA retrievals is studied. Results show negligible biases above random noise when QAA-derived b<sub>bp</sub> is compared to in situ b<sub>bp</sub>. In addition, R<sub>rs</sub> from the CCI archive shows good agreement with in situ data. The QAA&#8217;s functional form of spectral backscattering slope, as derived from in situ radiometry, is validated. Finally, we show the importance of correcting for Raman Scattering over clear waters prior to semi-analytical retrieval. Overall, this work demonstrates the high efficiency of QAA in the b<sub>bp</sub> detection in case of both in situ and ocean color data, but it also highlights the necessity to increase the number of observations that are severely under-sampled in respect to others environmental parameters.