Optical depth data vs. volcanic SO2 emissions prior satellite age: using standardised volcanic plume heights for moderate-scale eruptions

Prior to satellite age it is still a challenge to estimate volcanic sulfur gas loading into the atmosphere and stratosphere, respectively. Estimation of volcanic gas injection into the stratosphere needs data considering not only quantity of volcanic gas released via explosive eruptions but also information of volcanic plume heights, a volcano`s coordinates and the annual season of an eruption. This study wants to decipher the atmospheric impact of rather unknown and less good monitored historic volcanic eruptions. The focus is, mainly, on the years between 1920-1960 because the anthropogenic sulfuric gas input into the atmosphere is considered below average low compared to the remaining past century.