São Francisco’s Colorful Palette

This Dec. 27, 2023 image of the São Francisco River in southeast Brazil showcases the range of vibrant colors in the area including blues, reds, greens, and yellows. Much of the unvegetated land, such as unplanted fields and unpaved roads, appears in bright shades of red and yellow. This coloration comes from the underlying clays and soils of Brazil’s state of Minas Gerais.

The photo focuses on the Três Marias Reservoir, a human-made waterbody fed by the São Francisco River. Access to freshwater for irrigation enables agriculture around the reservoir. Red- and green-toned areas can be distinguished as fields with center-pivot irrigation or straight-edged plots. An orange-tan contour line tracing the shoreline of the reservoir marks where water levels have been higher. The lighter shades of blue on the reservoir’s surface are due to sunglint, an optical effect that occurs when sunlight reflects off smooth water at the same angle a sensor views it.

Text credit: Andrea Wenzel

Image credit: NASA