Large Cities May Create Their Own Clouds

sciencehabit shares a report from Science Magazine: Although it’s well-known that concrete-rich cities are often several degrees hotter than the leafy suburbs, scientists have now determined that cities are also capable of prolonging their own cloud cover. By studying satellite imagery of London and Paris, scientists discovered that during the spring and summer, the modern megacities are persistently cloudier in the afternoon and evening, by several percentage points, than nearby rural areas. Using ground-based observations in London, the researchers suggest the heat retained by buildings into the late afternoon drives turbulence in the air, feeding moisture to the clouds, they report this month in Climate and Atmospheric Science.