redOrbit: The frequency of extremely high clouds in Earth’s tropics — the type associated with severe storms and rainfall — is increasing as a result of global warming, according to a study by scientists at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. In a presentation yesterday to the fall meeting of the American Geophysical Union in San Francisco, JPL Senior Research Scientist Hartmut Aumann outlined the results of a study based on five years of data from the Atmospheric Infrared …