Suspended particulate matter dynamics in coastal waters from ocean color: Application to the northern Gulf of Mexico

Abstract

Suspended particulate matter (SPM) plays an important role in primary production, pollutant transport, and other biogeochemical processes in coastal marine environments. We present an empirical two‐band ocean color remote sensing reflectance algorithm (R rs 670/R rs 555) for SPM concentrations developed using field measurements obtained in coastal waters influenced by the Mississippi River in 2000, 2002, and 2004. The ratio algorithm was also found to be highly correlated to backscattering coefficient ( b bp ( 555 ), r 2 = 0.96), the backscattering ratio ( b bp ( 555 )/ b p ( 555 ), r 2 = 0.82) and the spectral backscattering slope ( γ , r 2 = 0.72) in March 2002, a period with large hydrographic variability in the study area. Strong correlations between water column b bp ( 555 ), SPM and nonalgal absorption a nap ( 443 ) suggest the dominant influence of nonalgal particles on b bp . SeaWiFS derived SPM and γ distributions indicated event‐based variability linked to energetic disturbances such as frontal passages, resuspension, and river discharge that with b bp / b p could reveal refractive index and particle size characteristics in the coastal environment.