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Report on Atmospheric Effects (1980-1989) — August 1987

Scientific Event Alert Network Bulletin, vol. 12, no. 8 (August 1987)
Managing Editor: Lindsay McClelland.

Atmospheric Effects (1980-1989) Aerosols at 12 km mostly H2SO4 spheres; no new layers

Please cite this report as:

Global Volcanism Program, 1987. Report on Atmospheric Effects (1980-1989) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:8. Smithsonian Institution.

Atmospheric Effects (1980-1989)

All times are local (unless otherwise noted)

The last two Bulletins reported lower stratospheric layers, perhaps from forest fires in China. Since June, however, no evidence of these layers has been detected by lidar at Hampton, VA or Mauna Loa, Hawaii (figure 46). August profiles at Hampton were smooth, without significant sublayering. Altitudes of peak backscattering at Mauna Loa dropped from 26-29 km in July to 22-25 km in August. There were no indications of recent aerosol injections.

Figure with caption Figure 46. Lidar data from Virginia and Hawaii, showing altitudes of aerosol layers during August 1987. Note that some layers have multiple peaks. Backscattering ratios are for the ruby wavelength of 0.69 µm. Integrated values show total backscatter, expressed in steradians-1, integrated over 300-m intervals from 16-33 km at Mauna Loa and from the tropopause to 30 km at Hampton, Virginia. Altitudes of maximum backscattering ratios and coefficients are shown for each layer at Mauna Loa.

Samples taken on 3 August near San Francisco (about 37.7°N, 122.5°W) by a NASA aircraft at about 12 km altitude did not show unusual concentrations of aerosols. Most particles were H2SO4 spheres, with a few chlorides and nitrates. The size distribution was generally unimodal, with a mean geometric radius of 0.06 µm, but there was a small bulge at about 0.3 µm radius.

Information Contacts: Mary Osborn, NASA Langley Research Center, Hampton, VA 23665 USA; Thomas DeFoor, Mauna Loa Observatory, P. O. Box 275, Hilo, HI 23665 USA; Rudolf Pueschel, Mail Stop 245-5, NASA Ames Research Center, Moffett Field, California 94035 USA.