Atmospheric controls on ground-and space-based remote detection of volcanic ash injection into the atmosphere, and link to early warning systems for aviation hazard mitigation

Violent volcanic eruptions, common especially in Southeast Asia, pose an ongoing serious threat to aviation and local communities. However, the physical conditions at the eruptive vent are difficult to estimate. In order to tackle this problem, satellite imagery and infrasound can rapidly provide information about strong eruptions of volcanoes not closely monitored by on-site instruments. For example, the recent infrasonic array at Singapore, installed to support the coverage of the International Monitoring System, allows identification of nearby erupting volcanoes based on the characteristics of the recorded signal. But, due to its location close to the equator, seasonal changes in the wind velocity structure of the atmosphere strongly affect its potential to detect small volcanic eruptions at certain azimuths. To overcome this limit, infrasound could be augmented with satellite data. Yet, with the high average cloud cover in Southeast Asia, there are also challenges to identify weak volcanic plumes using satellite-based monitoring techniques. In this chapter, we aim to examine the relative strengths and weaknesses of the two technologies to better understand the possibility to improve overall detection capability by combining infrasound with satellite imagery.