Porto Alegre Sunset and Glitter

August 05, 2007


Provided by: Marnes Augusto Hoff
Summary authors & editors: Jim Foster, Marnes Augusto Hoff

The photo above shows a brilliant orange sky sunset taken from Porto Alegre, Brazil (17:19 local time or UTC 20:19). This body of water is known as "Rio Guaíba" (Guaíba River), but it's actually an estuary. When the Sun is close to the horizon, whether at sunrise or sunset, on occasion the sky can quickly turn bright red or orange. This is especially true if high or mid-level clouds are present. However, if during the day aerosols are introduced either by human activities or thermal currents, then the mid-range part of the visible spectrum (green colors) may be more readily attenuated, leading to deeper reds at dusk. Note also the impressive glitter patch, which results from multiple reflections off of the small waves. Photo taken on June 24, 2006.

Related Links: