Particle Size Parameters of Particulate Matter Suspended in Coastal Waters and Their Use as Indicators of Typhoon Influence

• Published in: Remote sensing (Basel, Switzerland) Vol. 12; no. 16; p. 2581
• Main Authors: Liu, Yanxia, Huang, Haijun, Yan, Liwen, Yang, Xiguang, Bi, Haibo, Zhang, Zehua
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2020
• Subjects: Algorithms; Coastal processes; Coastal waters; Coasts; Efficiency; Estuaries; Fluxes; Geology; Indicators; Kurtosis; Mathematical models; Mie scattering; MODIS; Optical properties; Parameter estimation; Particle size; Particle size distribution; particle size parameters; Particulate matter; Power law; Remote monitoring; Remote sensing; remote sensing reflectance; Seawater; Sediments; Size distribution; slope of the power law PSD; Standard deviation; Theory; typhoon effect; Typhoons
• ISSN: 2072-4292; 2072-4292
• DOI: 10.3390/rs12162581

The power law particle size distribution (PSD) slope parameter is commonly used to characterize sediment fluxes, resuspension, aggregates, and settling rates in coastal and estuarine waters. However, particle size distribution metrics are also very useful for understanding sediment source and dynamic processes. In this study, a method was proposed to employ the particle size parameters commonly used in sedimentary geology (average particle size (ø), sorting, skewness, and kurtosis) as indicators of changes in sediment dynamic processes, and MODIS images were used to estimate these parameters. The particle size parameters were estimated using a Mie scattering model, Quasi-Analytical Algorithm (QAA) analysis algorithm, and least squares QR decomposition (LSQR) solution method based on the relationship between the power law distribution of the suspended particles and their optical scattering properties. The estimates were verified by field measurements in the Yellow Sea and Bohai Sea regions of China. This method provided good estimates of the average particle size (ø), sorting, and kurtosis. A greater number of wavebands (39) was associated with more accurate particle size distribution curves. Furthermore, the method was used to monitor changes in suspended particulate matter in the vicinity of the Heini Bay of China before and after the passage of a strong storm in August 2011. The particle size parameters represented the influence of a strong typhoon on the distribution of the near-shore sediment and, together with the PSD slope, comprehensively reflected the changes in the near-shore suspended particulate matter. This method not only established the relationship between remote sensing monitoring and the historical sediment record, it also extends the power law model to the application of sediment source and dynamic processes in coastal waters.