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A neural network‐based method for merging ocean color and Argo data to extend surface bio‐optical properties to depth: Retrieval of the particulate backscattering coefficient
Author(s) -
Sauzède R.,
Claustre H.,
Uitz J.,
Jamet C.,
Dall'Olmo G.,
D'Ortenzio F.,
Gentili B.,
Poteau A.,
Schmechtig C.
Publication year - 2016
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2015jc011408
Subject(s) - argo , satellite , ocean color , sea surface temperature , environmental science , remote sensing , artificial neural network , physical oceanography , meteorology , geology , computer science , climatology , artificial intelligence , geography , engineering , aerospace engineering
The present study proposes a novel method that merges satellite ocean color bio‐optical products with Argo temperature‐salinity profiles to infer the vertical distribution of the particulate backscattering coefficient (b bp ) . This neural network‐based method (SOCA‐BBP for Satellite Ocean‐Color merged with Argo data to infer the vertical distribution of the Particulate Backscattering coefficient) uses three main input components: (1) satellite‐based surface estimates of b bp and chlorophyll a concentration matched up in space and time with (2) depth‐resolved physical properties derived from temperature‐salinity profiles measured by Argo profiling floats and (3) the day of the year of the considered satellite‐Argo matchup. The neural network is trained and validated using a database including 4725 simultaneous profiles of temperature‐salinity and bio‐optical properties collected by Bio‐Argo floats, with concomitant satellite‐derived products. The Bio‐Argo profiles are representative of the global open‐ocean in terms of oceanographic conditions, making the proposed method applicable to most open‐ocean environments. SOCA‐BBP is validated using 20% of the entire database (global error of 21%). We present additional validation results based on two other independent data sets acquired (1) by four Bio‐Argo floats deployed in major oceanic basins, not represented in the database used to train the method; and (2) during an AMT (Atlantic Meridional Transect) field cruise in 2009. These validation tests based on two fully independent data sets indicate the robustness of the predicted vertical distribution of b bp . To illustrate the potential of the method, we merged monthly climatological Argo profiles with ocean color products to produce a depth‐resolved climatology of b bp for the global ocean.