Lidar data from Hawaii, Japan, and Germany generally showed continuing low concentrations of stratospheric aerosols (figure 64. A broad layer centered at about 24 km altitude was detected over Mauna Loa, Hawaii on 26 January, but its profile was not characteristic of newly injected material. At Fukuoka, Japan, peak backscattering increased slightly in December and January, to levels last measured shortly after the May eruption of Banda Api, Indonesia.

Figure 64. Lidar data from various locations, showing altitudes of aerosol layers during December 1988-January 1989. Note that some layers have multiple peaks. Backscattering ratios from Fukouka, Japan, are for the Nd-YAG wavelength of 1.06 µm; all others 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. Some upper and lower limits of layers at Mauna Loa were not clearly evident and are therefore not reported.

No recent eruptions appear to have produced clouds that reached the stratosphere. Observations of the December-January eruption of Lonquimay, Chile from the ground and from weather satellites revealed no clouds exceeding 9 km altitude. Weather conditions hampered observations during the December-January eruption of Tokachi-dake, Japan, and no large eruption clouds were seen, although ash fell tens of kilometers away.

Information Contacts: Thomas DeFoor, Mauna Loa Observatory, P.O. Box 275, Hilo, HI 96720 USA; Motowo Fujiwara, Physics Department, Fukuoka University, Jonan-ku, Fukuoka 814-01, Japan; Horst Jäger, Fraunhofer-Institut für Atmosphärische Umweltforschung, Kreuzeckbahnstrasse 19, D-8100 Garmisch-Partenkirchen, West Germany.