Scientists used observations from two NASA satellite instruments, including relative humidity data similar to these, from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft, to analyze how well leading global climate models reproduce observed relative humidity in Earth's tropics and subtropics. The study found climate models that most accurately captured these complex moisture processes and associated clouds were also the ones that showed the greatest amounts of warming as atmospheric greenhouse gases increase. The AIRS surface relative humidity data shown here are representative only and are not from the study. Areas shown in reds and yellows are the driest; blue areas the moistest. Credit: NASA/JPL-Caltech