Report on Atmospheric Effects (1980-1989) — November 1986
Scientific Event Alert Network Bulletin, vol. 11, no. 11 (November 1986)
Managing Editor: Lindsay McClelland.
Atmospheric Effects (1980-1989) Enhanced aerosols persist; perhaps brought from tropics by seasonal winds
Please cite this report as:
Global Volcanism Program, 1986. Report on Atmospheric Effects (1980-1989) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 11:11. Smithsonian Institution.
Atmospheric Effects (1980-1989)
All times are local (unless otherwise noted)
Lidar stations continued to detect increased stratospheric aerosols in November (figure 33). At Mauna Loa, Hawaii, a substantial increase in both peak and total backscatter was measured 18 November and numerous tiny sharp peaks were evident on initial data. From Fukuoka, Japan, very sharp peaks were recorded between 20.5 and 22 km altitude on 10, 17, and 21 November. Lidar at Hampton, VA detected both increased total backscatter and the presence of new higher-latitude layers in late November and early December. A thin layer at 21 km altitude was measured from Garmisch-Partenkirchen, Germany on 7 November, slightly higher than another new layer that had been observed on 24 October.
No eruption columns are known to have penetrated the stratosphere since the November 1985 eruption of Ruiz, although a brief strong explosive eruption occurred at Etna on 24 September, shortly before the initial appearance of increased aerosols. M. P. McCormick suggested the following interpretation for the observations.
"At certain times of the year, SAGE and SAGE II satellite observations show layers at altitudes well above the 'normal' stratospheric aerosol peak for that particular latitude. A clear seasonal cycle has become evident in both hemispheres, showing low-latitude type layers outside the equatorial belt in late fall and winter periods, with very few cases observed in summer (figure 34). The most obvious explanation for this 'extra' layer is that we are observing transport of low-latitude aerosols into the winter hemisphere by planetary wave activity, which is greater in the winter hemisphere. Care must be given, therefore, to interpreting local measurements by lidar or made in situ which show this type of layer as possibly due to a new volcanic eruption."
Information Contacts: M.P. McCormick and William Fuller, NASA Langley Research Center, Hampton, VA 23665 USA; Thomas DeFoor, Mauna Loa Observatory, P.O. Box 275, Hilo, HI 96720 USA; Motowo Fujiwara, Physics Department, Kyushu University, Fukuoka 812, Japan; H. Jäger, Fraunhofer-Institut für Atmosphärische Umweltforschung, Kreuzeckbahnstrasse 19, D-8100 Garmisch-Partenkirchen, West Germany.