Mount Pinatubo

Solomon S, Sanders RW, Garcia RR, et al. 1993. Increased chlorine dioxide over Antarctica caused by volcanic aerosols from Mount Pinatubo. Nature 363 245-248. 

There are several reasons for the dramatic ozone destruction (see Fig. 2.17) low temperatures may have prolonged the presence of polar stratospheric clouds, which play a key role in the ozone destruction, the polar vortex was very stable, there were increased sulfate aerosols from the 1991 Mount Pinatubo volcanic eruption, which also contribute to heterogeneous chemistry, and chlorine levels had continued to increase. These issues are treated in more detail shortly. 

Another method of probing sulfuric acid aerosols is to heat the sample intake sufficiently to vaporize sulfuric acid-water aerosols but not other particles such as those containing ash minerals the difference between the measured particles with and without intake heating provides a measure of the contribution of sulfuric acid-water. Using this technique, Deshler et al. (1992), for example, have shown that more than 90% of the stratospheric particles above Laramie, Wyoming, after the Mount Pinatubo eruption were composed of sulfuric acid-water mixtures. 

Figure 12.28 shows the particle surface area size distribution before the Mount Pinatubo eruption (Fig. 12.28a), inside the main aerosol layer several months after the eruption (Fig. 12.28b), and almost two years after the eruption (Fig. 12.28c). (See Chapter 9.A.2 for a description of how particle size distributions are normally characterized.) Prior to the eruption, the surface area distribution is unimodal, with typical radii of 0.05-0.09 /xrn and a number concentration of l-20 particles cm 1. In the main stratospheric aerosol layer formed after the eruption, the distribution is bimodal...

Figure 12.29 shows the ratio of the particle surface area at an altitude of 20 km and 45°N latitude to that in 1978-1979 for the period from 1979 to 1995 based on satellite measurements (Solomon et al., 1996). The increases due to volcanic eruptions are evident, particularly the Mount Pinatubo eruption. 

Laboratory studies of the uptake of CIO into sulfuric acid (Martin et al., 1979, 1980), taken in light of a deficit in the inorganic chlorine budget at 17 km after the Mount Pinatubo eruption, led Jaegle et al. (1996) to propose that a heterogeneous reaction of CIO on sulfuric acid aerosols to form perchloric acid, HC104, may also occur. 

FIGURE 12.28 Particle surface area distributions in the stratosphere (a) before Mount Pinatubo eruption, (b) August 20, 1991, over California, and (c) May 7, 1993, over California (adapted from Russell et al. (1996) and Goodman et al. (1994)). 

There are a number of measurements documenting changes in NO and NO. in the stratosphere after the Mount Pinatubo eruption and which have been attributed to the removal of oxides of nitrogen due to reactions on aerosol particles. For example, a decrease in stratospheric NOz after the eruption followed by a return to normal levels has been reported (e.g., see Van Roozendael et al., 1997 and De Maziere et al., 1998). Similarly, NO decreases of up to 70% were reported, as well as increases in gaseous HN03 (much of that produced on the sulfate particles is released to the gas phase) (e.g., see Coffey and Mankin, 1993 Koike et al., 1993, 1994 David et al., 1994 Webster et al., 1994 and Rinsland et al., 1994). 

A similar relationship was observed in Germany. Figure 12.36, for example, shows the deviation of the monthly mean ozone concentration after corrections for seasonal variations, long-term trends, the QBO and vortex effects, and the associated particle surface area concentration from 1991 to 1994 (Ansmann et al., 1996). The increase in the particle surface area due to Mount Pinatubo is clear associated with this increase in aerosol particles are negative monthly mean deviations in ozone that persist until fall 1993, when the surface area approaches the preeruption values. Similarly, the decrease in the total column ozone from 1980-1982 to 1993 observed at Edmonton, Alberta, Canada, and shown at the beginning of this chapter in Fig. 12.1 has been attributed to the effects of the Mount Pinatubo eruption (Kerr et al., 1993). 

Anderson, J., and V. K. Saxena, Temporal Changes of Mount Pinatubo Aerosol Characteristics over Northern Midlatitudes Derived from SAGE II Extinction Measurements, J. Geophys. Res., 101, 19455-19463 (1996). 

De Maziere, M M. Van Roozendael, C. Hermans, P. C. Simon, P. Demoulin, G. Roland, and R. Zander, Quantitative Evaluation of the Post-Mount Pinatubo N02 Reduction and Recovery, Based on 10 Years of Fourier Transform Infrared and UV-Visi-ble Spectroscopic Measurements at Jungfraujoch, J. Geophys. Res., 103, 10849-10858 (1998). 

D. Nganga, A. Minga, B. Cros, C. F. Butler, M. A. Fenn, C. S. Long, and L. L. Stowe, Aerosol-Associated Changes in Tropical Stratospheric Ozone Following the Eruption of Mount Pinatubo, J. Geophys. Res., 99, 8197-8211 (1994). 

Mickley, L. J., J. P. D. Abbatt, J. E. Frederick, and J. M. Russell III, Response of Summertime Odd Nitrogen and Ozone at 17 mbar to Mount Pinatubo Aerosol over the Southern Midlatitudes Observations from the Halogen Occultation Experiment, J. Geophys. Res., 102, 23573-23582 (1997a). 

Stone, R. S., J. R. Key, and E. G. Duton, Properties and Decay of Stratospheric Aerosols in the Arctic Following the 1991 Eruptions of Mount Pinatubo, Geophys. Res. Lett., 20, 2359-2362 (1993). Strand, A, and 0. Hov, The Impact of Man-Made and Natural NOA. Emissions on Upper Tropospheric Ozone A Two-Dimensional Model Study, Atmos. Enriron., 30, 1291-1303 (1996). 

Hansen, J., A. Lacis, R. Ruedy, and M. Sato, Potential Climate Impact of Mount Pinatubo Eruption, Geophys. Res. Lett., 19, 215-218(1992). 

Sny material in the atmosphere that is harmful to health is defined as an air pollutant. One major source of air pollutants is volcanoes. The largest volcanic blast of the 20th century, for example, was the 1991 eruption of Mount Pinatubo in the Philippines, which released 20 million tons of the noxious gas sulfur dioxide, S02. As Figure 17.7 shows, this sulfur dioxide managed to travel all the way to India in only 4 days. 

The cloud of sulfur dioxide generated by the June 15,1991, eruption of Mount Pinatubo reached India in 4 days. (The black strips indicate missing satellite data.) By July 27, the sulfur dioxide cloud had traveled around the globe. 

Goodman, J., K.G. Snetsinger, R.F. Pueschel, and S. Verma (1994) Decay of Mount Pinatubo volcanic perturbation, Geophys. Res. Lett. 21,1129-1132. 

It is probable that the cold summer of 1982 in the Black Sea as well as in the Mediterranean Sea [30] and in the northeastern Atlantic [31] was caused by the aerosols from the El Chichon (Mexican volcano) eruption in April 1982 [18]. Similarly, the eruption of Mount Pinatubo (Philippines volcano) in June 1991, whose after-effects were traced in the atmosphere of the Northern Hemisphere up to 1995 (as follows from the modeling results), might also make its contribution to the anomalously cold winter and summer of 1993 [32]. It is interesting that both of these volcanic eruptions coincided with the El Nino events of 1982-1983 and 1990-1995. 

Kirchner I., Stenchikov G., Graf H.-F., Robock A., and Antuna J. (1999) Climate model simulation of winter warming and summer cooling following the 1991 Mount Pinatubo volcanic eruption. J. Geophys. Res. 104, 19039-19055. 

Radiative forcing from the 1991 Mount Pinatubo volcanic eruption. J. Geophys. Res. 103, 13837-13857. 

Wallace P. J. and Gerlach T. M. (1994) Magmatic vapor source for the sulfur dioxide released during volcanic eruptions evidence from Mount Pinatubo. Science 265, 497-499. 

Westrich H. R. and Gerlach T. M. (1992) Magmatic gas source for the stratospheric SO2 cloud from the June 15, 1991 emption of Mount Pinatubo. Geology 20, 867-870. Williams S. N. (1983) PUnian airfall deposits of basaltic... 

Hattori K. H. and Keith J. D. (2002) Contribution of mafic melt to porphyry copper minerahzation evidence from Mount Pinatubo, Phihppines, and Bingham Canyon, Utah, USA. Mineral. Dep. 36, 799—806. 

Aerosol particles resulting from the 1991 eruption of Mount Pinatubo (Philippines) are widely cited in the recent atmospheric literature because of their global effects on atmospheric radiation and climate (Hansen et al., 1992 McCormick et al., 1995). However, volcanic eruptions occur every year, and some have been far larger than Pinatubo. For comparison, Krakatoa (1883 between Java and Sumatra, Indonesia) and Tambora (1815 Sumbawa, Indonesia), respectively, emitted double and ten times as much pyroclastic debris into the atmosphere as Pinatubo, and significantly reduced sunlight around the globe for months (Sparks et al., 1997). Their effects on the atmosphere have been profound. 

Hansen J., Lacis A., Ruedy R., and Sato M. (1992) Potential chmate impact of Mount Pinatubo eruption. Geophys. Res. Lett. 19, 215-218. 

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