Evolution of CO₂, SO₂, HCl, and HNO₃in the volcanic plumes from Etna

Abstract

The volcanic plumes from degassing Etna (Italy) were extensively probed with instruments onboard the Deutsches Zentrum für Luft‐ und Raumfahrt research aircraft Falcon during the contrail, volcano, and cirrus experiment CONCERT on 29/30 September 2011. Up to 10.4 ppmv SO2and 0.3 ppmv HCl were detected with the atmospheric chemical ionization mass spectrometer AIMS at 3.1 km altitude and 20 km distance to the summit. HNO3 is the dominant reactive nitrogen component in the plumes. Linking aircraft and ground‐based observations by Hybrid Single‐Particle Lagrangian Integrated Trajectory dispersion modeling, we identify two crater plumes with different compositions primarily injected by the Bocca Nuova and North East craters. Uniquely, we follow their chemical evolution up to 5 h plume age. Our results show that CO2/SO2and SO2/HCl molar ratios are stable in the ageing plumes. Hence, conversion of SO2 to H2SO4 and partitioning of HCl in acidic plume particles play a minor role at dry tropospheric conditions. Thus, these trace gases allow monitoring volcanic activity far from the crater.

The airborne mass spectrometer AIMS – Part 1: AIMS-H<sub>2</sub>O for UTLS water vapor measurements

“…AIMS-H 2 O flew on the DLR Falcon in 2011 Voigt et al, 2014) and on HALO during the ML-CIRRUS experiment in March/April 2014. In order to provide an example of the performance of AIMS-H 2 O, the water vapor time series of flight 9 on 7 April 2014 is shown in Fig.…”

Potential of airborne lidar measurements for cirrus cloud studies

“…The airborne in situ hygrometer instrument WARAN consists of a commercial tunable diode laser (TDL) device (WVSS-II, Spectrasensors Inc.; Voigt et al, 2014) in combination with a Rosemount inlet system. The WVSS-II is a closedcell TDL system in which a diode laser is tuned continuously over the water vapour absorption line at 1.37 µm.…”

Reply to comment from Liotta and Rizzo on “Evolution of CO2, SO2, HCl and HNO3 in the volcanic plumes from Etna” by Voigt et al. [Geophys. Res. Lett.; 41, doi:10.1002/2013GL058974]

“…R1 and Fig. 1 in Voigt et al (2014)) clearly show two plume layers spreading out above 3 km altitude in the free troposphere on both days, indicating plume origins from at least two craters. We derive mean bulk and layer-resolved CO 2 /SO 2 and SO 2 /HCl molar ratios in the plumes.…”

“…First, we summarize the paper "Evolution of CO 2 , SO 2 , HCl and HNO 3 in the volcanic plumes from Etna" by Voigt et al (2014), and thereafter, we discuss the comment by Liotta and Rizzo (2014). In Voigt et al (2014), we present novel in situ measurements of the composition of the volcanic plumes from the degassing Etna (Italy), performed with the DLR research aircraft Falcon during the CONCERT contrails, volcanos and cirrus experiment on 29 and 30 September 2011.…”

“…In Voigt et al (2014), we present novel in situ measurements of the composition of the volcanic plumes from the degassing Etna (Italy), performed with the DLR research aircraft Falcon during the CONCERT contrails, volcanos and cirrus experiment on 29 and 30 September 2011. Trace gas mixing ratios of SO 2 , HCl and HNO 3 were measured using mass spectrometry.…”