Figure 4

Mean salinity differences from WOS in the surface (the top two layers) river plume area (salinity ≤ 28.0), in sensitivity experiments with respect to changes in SSM input (x-axis) and diameter (y-axis), at the times of maximum differences. The SSM inputs of the x-axis are normalized by those of STD. Numbers on the lower x-axis are the density differences between river water and seawater, approximately calculated from the maximum amounts of input SSM and freshwater, temperature, and salinity in the initial state. Negative values (blue color) indicate lower salinity (i.e., a more intense hypopycnal plume) than WOS, whereas positive values (brown color) denote higher salinity (i.e., a hyperpycnal plume). The purple circle marks a typical hypopycnal case and the yellow circle a typical hyperpycnal one. nodim. non-dimensional.