Re‐evaluation of SO₂ release of the 15 June 1991 Pinatubo eruption using ultraviolet and infrared satellite sensors

Abstract

In this study, ultraviolet TOMS (Total Ozone Mapping Spectrometer) satellite data for SO2 are re‐evaluated for the first 15 days following the 15 June 1991 Pinatubo eruption to reflect new data retrieval and reduction methods. Infrared satellite SO2 data from the TOVS/HIRS/2 (TIROS (Television Infrared Observation Satellite) Optical Vertical Sounder/High Resolution Infrared Radiation Sounder/2) sensor, whose data sets have a higher temporal resolution, are also analyzed for the first time for Pinatubo. Extrapolation of SO2 masses calculated from TOMS and TOVS satellite measurements 19–118 hours after the eruption suggest initial SO2 releases of 15 ± 3 Mt for TOMS and 19 ± 4 Mt for TOVS, including SO2 sequestered by ice in the early Pinatubo cloud. TOVS estimates are higher in part because of the effects of early formed sulfate. The TOMS SO2 method is not sensitive to sulfate, but can be corrected for the existence of this additional emitted sulfur. The mass of early formed sulfate in the Pinatubo cloud can be estimated with infrared remote sensing at about 4 Mt, equivalent to 3 Mt SO2. Thus the total S release by Pinatubo, calculated as SO2, is 18 ± 4 Mt based on TOMS and 19 ± 4 Mt based on TOVS. The SO2 removal from the volcanic cloud during 19–374 hours of atmospheric residence describes overall e‐folding times of 25 ± 5 days for TOMS and 23 ± 5 days for TOVS. These removal rates are faster in the first 118 hours after eruption when ice and ash catalyze the reaction, and then slow after heavy ash and ice fallout. SO2 mass increases in the volcanic cloud are observed by both TOMS and TOVS during the first 70 hours after eruption, most probably caused by the gas‐phase SO2 release from sublimating stratospheric ice‐ash‐gas mixtures. This result suggests that ice‐sequestered SO2 exists in all tropical volcanic clouds, and at least partially explains SO2 mass increases observed in other volcanic clouds in the first day or two after eruption.

Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

“…The results obtined in this study and by Jurkat et al (2010) are based on aircraft measurements at altitudes of 7-12 km, which is just below the center of the volcanic cloud as observed by sattelites. The volcanic cloud that was observed by satellite following the Pinatubo eruption was injected well into the stratosphere to altitudes of ∼25 km (Guo et al, 2004). Thus the longer residence times meassured by aircraft might be typical for the altitude and latitude considered.…”

“…Estimations of the conversion rate of SO 2 following the Pinatubo eruption are less dispersed; 35 days (Bluth and Doiron, 1992), 33 days (Read et al, 1993) and 25 ± 5 as well as 23 ± 5 days (Guo et al, 2004). Except in the work by Guo et al (2004), uncertainty of the estimated residence time has not been given. Thus it is difficult to compare the validity of our estimate to others.…”

Climatic and societal impacts of a volcanic double event at the dawn of the Middle Ages

“…1). For consistency with modern observations of the height of SO 2 injection from the 1991 Pinatubo eruption (Guo 2004), an injection height of 30 hPa is also assumed for the tropical 540 event.…”

Earth Observations from DSCOVR EPIC Instrument

“…7) has been made (Herman et al 2018) with the assimilated ozone product from the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), based on Microwave Limb Sounder (MLS) and total column ozone from the OMI. All of the structures in the EPIC ozone retrieval are present in the MERRA-2 (Bluth et al 1993(Bluth et al , 1997Carn et al 2003Carn et al , 2015Carn et al , 2016Carn and Krotkov 2016;Guo et al 2004;Krotkov et al 1999a,b;Krueger 1983;Krueger et al 1995Krueger et al , 2000Li et al 2017;Pavolonis et al 2013;Prata 1989;Prata and Kerkmann 2007;Prata et al 2003Realmuto 2000;Wen and Rose 1994 (Prata 1989;Realmuto 2000;Ackerman et al 2008;Pavolonis et al 2013). DSCOVR EPIC provides the first opportunity to observe transient volcanic clouds globally from L1.…”