The grain-size distribution of the suspended particulate matter in the Huanghe Estuary and its adjacent sea area in winter

The grain-size of suspended particulate matter (SPM) in the Huanghe Estuary and its adjacent sea area was investigated with an in situ laser particle size analyzer (LISST-100) in November 2006. The spatial distribution of the grain-size parameters was very complicated. The results show that (1) the mean particle size of SPM ranged from 3.00Φ to 6.41Φ, with an average value of 4.66Φ; (2) the frequency distribution patterns of the SPM grain-size showed three different types, which were mono-mode, dual-mode and tri-mode, respectively; (3) C-M chart suggested that the transportation-processes of the SPM not only included suspended mode, but also the bed load transportation mode. The bed load transportation mode mainly occurred at the bottom layer. The characteristics and space distribution of SPM grain-size might be mainly controlled by sediment discharge of the Huanghe River, hydrodynamics condition, surface sediment types, and biological process within the study area.