AIRS Image of 21W (IMAGE) NASA/Goddard Space Flight Center Caption This false-colored infrared image from the AIRS instrument aboard NASA's Aqua satellite shows cold cloud top temperatures (purple) of Tropical Depression 21W on Sept. 21 at 16:17 UTC (12:17 p.m. EDT). Credit Credits: NASA JPL, Ed Olsen Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.