People have long noticed that the waters around Cabo Frio are unusually cool.
When European explorers first surveyed the coastline of what is now the state of Rio de Janeiro in the early 1500s, they encountered white sands, turquoise waters, shallow lagoons, and lush green mountains rising from the sea. The waters in one area, however, were unusually cool—so much so that the promontory in southeastern Brazil shown above was named Cabo Frio, Portuguese for “Cape Cold.”
Landsat 9’s OLI-2 (Operational Land Imager-2) captured this image of Cabo Frio’s diverse coastline on September 16, 2023. The map (below) shows that surface waters that day were cooler off of Cabo Frio than in the surrounding waters. The pattern is common: Upwelling of cold water from deeper in the ocean to the surface often chills Cabo Frio’s surface waters by several degrees.