Nasa has combined the images of two satellites to produce a more detailed view of the ash plume from Iceland’s Eyjafjallajökull Volcano. The top image is from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. The lower image is from NASA’s CALIPSO satellite which uses a pulsating laser (lidar) to measure where clouds and ash are located in the atmosphere.
Many satellites can provide a bird’s-eye view (such as the top, nighttime image) that can identify thick plumes of ash, but few satellites can tell how high the ash is in the atmosphere. NASA’s Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, however, records a vertical profile of the atmosphere, which reveals the altitude of ash clouds, shown in the lower image. These observations help modelers in volcanic ash advisory centers improve forecasting models and issue more accurate warnings to pilots and others with aviation interests.
