Optimal Use of Satellite Data Applications for the Volcanic Ash Threat to Aviation

Over the past decade, the public interest has been increasingly focused on the significant safety and economic impacts of the volcanic ash threat to aviation. This interest has especially increased since the eruption of Eyjafjallajökull substantially disrupted aviation operations throughout Europe. During this period, the NASA Applied Science Program developed a significant number of critical volcanic ash applications for a wide range of cutting-edge NASA satellite observations. This has entailed the development of many new and innovative technical advances. These advances have enabled and are increasingly improving the accuracy and the utility of volcanic ash advisories worldwide. None of these observations alone, however, provides a panacea for improving volcanic ash advisories. This paper highlights the strengths of various applications for five currently deployed NASA research satellites, many of which are in use operationally by Volcanic Ash Advisory Centers. An important and more general take-away from this presentation, however, is that since state-of-the-art atmospheric dispersion models are so highly sensitive to initial conditions, multi-disciplinary observations of the source plume and the dispersed ash cloud using a wide variety of observations, including satellites, in situ measurements, forward-looking sensors and other methods should be concomitantly employed.

A substantial legacy rests on NASA Earth Observing Satellites and their advanced data. Imager applications for the The MODerate Resolution Imaging Spectro-radiometer (MODIS) instrument onboard NASA Terra and Aqua spacecraft and the Visible Infrared Imager Radiometer Suite (VIIRS) instrument onboard Suomi NPP provides better discrimination of ash from water vapor and ice clouds than traditional split-window imager techniques, as well as improved height assignment. Chemistry and aerosol applications for the Ozone Monitoring Instrument (OMI) onboard the NASA Aura spacecraft and the Ozone Mapper and Profiler Suite (OMPS) onboard Suomi NPP produce improved horizontal dispersion maps, and indices for volcanic ash and sulfate aerosol concentrations. Applications for the Caliop lidar onboard the NASA Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite provide very accurate estimates of volcanic ash altitude, layering, concentration and various aerosol properties. These are critical assimilation elements for volcanic ash dispersion models and forecasts. The Multi-angle Imaging SpectroRadiometer (MISR) instrument onboard Terra provides unique stereoscopic data for volcanic ash that is critical for resolving the altitude and extent of volcanic ash layers and for calibration and validation of the other volcanic ash applications. All of these satellite data and applications, together with other sources of information on volcanic ash in the atmosphere should be better examined and assimilated to improve the initial state of volcanic ash dispersion models and, ultimately, model forecasts of the volcanic ash threat to aviation.