In Brazil, the Amazon River has bicolor tributary flows. The two colors of the Amazon River basin were observed by GOSAT.
Brazilian city observed by TANSO-CAI on August 13, 2019. The Negro River is in black color in the upper left of figure 1. The Solimoes River is composed with the red color in the south of the Negro River in figure 1※, but the visible true color is brown. These two rivers join near Manaus City and flow with keeping two colors through the length of 10 km. The reason not to be mixed depends on the difference of water properties between the two rivers. It is affected by speed, water temperature and pH level of the rivers. Figure 2 shows the Amazon River Estuary observed by TANSO-CAI on September 5, 2019. The water component similar to the Solimoes River flows out to the sea around Santa Rosa Bay. The water of the Amazon River is mixed with the seawater gradually, not quickly, with blending the different water properties.
※The TANSO-CAI image was composed of band2 (674nm) in red, band3 (870nm) in green and band1 (380nm) in blue.
NASA Solimões and Negro Rivers