Atmospheric implications of studies of Central American volcanic eruption clouds

Abstract

During February 1978 a group of scientists from the National Center for Atmospheric Research, several colleges and universities, the U.S. Geological Survey, and NASA used a specially equipped Beech Queen Air aircraft to make 11 sampling flights in Guatemala through the eruption clouds from the volcanoes Pacaya, Fuego, and Santiguito. Measurements were made of SO42−, SO2, HCl, HF, and 11 cations that were in water‐soluble form, on samples collected by a specially designed filter pack. Particle size distributions were obtained with a piezoelectric cascade impactor, and the particles were identified by energy dispersive X ray analysis. Evacuated canisters were flown to obtain samples for gas Chromatographic analysis. Some of the conclusions reached are that since most of the sulfur was found to be in the form of SO2, the H2SO4 droplets resulting from major explosive eruptions must largely result from the reaction of SO2 with OH, at the same time depleting the atmosphere of OH; the volume concentration ratio [SO2]/[HCl] always somewhat exceeded unity; and the amount of fine ash remaining in the stratosphere for long periods of time may depend on the crystallinity of the magma. Correlation spectrometry showed that each volcano was emitting 300–1500 metric tons of SO2 per day.

Deposition of trace elements from high temperature gases of Satsuma-Iwojima volcano

“…Previous aerosol studies identified some of the metal bearing phases (Cadle et al, 1979;Rose et al, 1982;Hobbs et al, 1982;Mackinnon et al, 1984;Varekamp et al, 1986;Symonds and Reed, 1993;Toutain et al, 1995;Galindo et al, 1998) but could not provide information on the temperatures or conditions of the aerosols formation. Other solid phases probably present in the plumes might not be identified in the collected aerosols because of their low concentration or because of the small size of the particles (<1 μm).…”

Sulfur isotope fractionation during the May 2003 eruption of Anatahan volcano, Mariana Islands: Implications for sulfur sources and plume processes

“…Direct sampling of high temperature fumaroles represent compositions of gases derived from quiescent magma (Giggenbach, 1996;Fischer et al, 1997Fischer et al, , 1998; however, these compositions are variably affected by hydrothermal processes and direct sampling is impossible during explosive eruptions. Filter sampling of gases and particles from plumes provides information on eruptive gas compositions and plume processes and has led to the identification of sulfate and chloride salts and sulfuric acid aerosols as common products in the plume (Cadle et al, 1979;Smith et al, 1982;Casadevall et al, 1984;Rose et al, 1988Rose et al, , 2006. It has been estimated that $30% of the total emitted S can be scavenged from plumes by adsorption as sulfates onto ash, which is deposited (Rose, 1977;Varekamp et al, 1984;de Hoog et al, 2001a).…”

Monitoring of the integrated column of hydrogen fluoride above the Jungfraujoch Station since 1977 ? the HF/HCl column ratio

“…Despite some conjectures about the possible injection of hydrogen fluoride into the atmosphere by strong volcanic eruptions (Cadle et al, 1979), HF has no known significant sources in the troposphere, where its natural background concentration has been poorly monitored but appears to be very low (Cicerone, 1981).…”