Ballistics and ash plumes discriminated by Doppler radar

Airborne Doppler radar observations of convective plumes and radar ‘fine-lines’ ERAD02-A-00007

Reflectivities and Doppler velocities from an airborne 95 GHz radar are used to describe the detailed (~25 m) vertical structure of plumes and mesoscale convergence lines (‘fine-lines’) in the optically-clear convective boundary-layer (CBL). Multiple radar configurations are used, including a profiling mode, with fixed antennas looking up and down, and a vertical-plane dual-Doppler mode, employ...

Ash aggregation enhanced by deposition and redistribution of salt on the surface of volcanic ash in eruption plumes

Interactions with volcanic gases in eruption plumes produce soluble salt deposits on the surface of volcanic ash. While it has been postulated that saturation-driven precipitation of salts following the dissolution of ash surfaces by condensed acidic liquids is a primary mechanism of salt formation during an eruption, it is only recently that this mechanism has been subjected to detailed study....

Doppler Radar Observations

Doppler Radar Observations

Hail formation triggers rapid ash aggregation in volcanic plumes

During explosive eruptions, airborne particles collide and stick together, accelerating the fallout of volcanic ash and climate-forcing aerosols. This aggregation process remains a major source of uncertainty both in ash dispersal forecasting and interpretation of eruptions from the geological record. Here we illuminate the mechanisms and timescales of particle aggregation from a well-character...