Key Uncertainties

  • Characterize the short-term temporal variability and time-averaged budget of the volcanic source emissions during an eruption, in terms of gas-particle chemistry, mass fluxes, number concentration and size distribution of particles.

  • Constrain and quantify the near-source processes and evolving properties of volatile-derived and solid aerosols (chemical, microphysical, optical, radiative), including primary and secondary aerosols.

  • Characterize the dynamics and nature of macroscopic solid emissions (particles, from bombs to ash, and lava) at the source emission point/vent-exit in terms of size, morphology, componentry, texture and chemistry, temperature, flow-rate, injection height, and their evolution in time. This approach can be done in sampling the material on the ground (with TARP, ASHER, etc…), but the challenge is to sample and or measure pyroclast or lava in-situ (still hot and dynamic in the explosive jet at the vent-exit or in the moving lava) to preserve the original shape, size, texture, chemistry and rheology.

  • Quantify the high-temperature chemistry and identify chemical processes that may determine the reactive gas chemistry and aerosol lifecycle (gas-ash interaction, formation of sulfate precursors like SO3 and other radicals).

  • Improve modeling of the high-temperature gas chemistry at the source and low-temperature chemical evolution in the near-source plume, in order to define an “effective emissions source” for larger-scale atmospheric models.

  • Characterize the emissions of each volcano and its evolution with time as a function of their type of activity for both passive emissions and eruptions.

  • Reconcile the degassing budget based on the petrological investigations through difference between melt inclusion (pre-eruptive) and tephra (post-eruptive) volatile content, namely CHOS-halogen species.

  • Extend the estimations of emissions (gas and aerosols) from both passive degassing and in case of eruptions from well monitored volcanoes to all volcanoes over the globe.