Publications

Jafar-Sidik, M; Gohin, F; Bowers, D; Howarth, J; Hull, T (2017). The relationship between Suspended Particulate Matter and Turbidity at a mooring station in a coastal environment: consequences for satellite-derived products. OCEANOLOGIA, 59(3), 365-378.

Abstract
From a data set of observations of Suspended Particulate Matter (SPM) concentration, Turbidity in Formazin Turbidity Unit (FTU) and fluorescence-derived chlorophyll-a at a mooring station in Liverpool Bay, in the Irish Sea, we investigate the seasonal variation of the SPM: Turbidity ratio. This ratio changes from a value of around 1 in winter (minimum in January-February) to 2 in summer (maximum in May-June). This seasonal change can be understood in terms of the cycle of turbulence and of the phytoplankton population that affects the nature, shape and size of the particles responsible for the Turbidity. The data suggest a direct effect of delayed effect, likely due to aggregation of particles, in July and August. Based on the hypothesis that only SPM concentration varies, but not the mass-specific backscattering coefficient of particles b(bp)*, semi-analytical algorithms aiming at retrieving SPM from satellite radiance ignore the seasonal variability of b(bp)* which is likely to be inversely correlated to the SPM: Turbidity ratio. A simple sinusoidal modulation of the relationship between Turbidity and SPM with time helps to correct this effect at the location of the mooring. Without applying a seasonal modulation to b(bp)*, there is an underestimation of SPM in summer by the Ifremer semi-analytical algorithm (Gohin et al., 2015) we tested. SPM derived from this algorithm, as expected from any semi-analytical algorithm, appears to be more related to in situ Turbidity than to in situ SPM throughout the year. (C) 2017 The Authors. Production and hosting by Elsevier Sp. z o. o. on behalf of Institute of Oceanology of the Polish Academy of Sciences. This is an open access article under the CC BY-NC-ND license.

DOI:
10.1016/j.oceano.2017.04.003

ISSN:
0078-3234