The major stratospheric cloud remained dense over lower northern latitudes. It has been estimated to cover the earth from S of the equator to as far N as Japan between 21 and 33 km altitude and to average 9.6 km thick. Lidar measurements and reports from England indicated that gradual northward dispersal was continuing.

At Mauna Loa, Hawaii, lidar measurements showed that cloud material was densest at 25-27 km altitude. Lidar at Fukuoka, Japan showed increasing concentrations during July at 22-25 km altitude. Measurements of well-resolved fine structures on 26 July showed a more dense layer at 22-24 km and a less dense one at 28-29 km. The backscattering ratio of 42 at 25 km altitude detected 1 July by lidar at Hampton, Virginia was the highest ever observed in the stratosphere from there. Measurements from the 8-13 July NASA flight revealed several separate layers of material, with greatest concentrations between 24 and 26 km altitude.

As observed from Norwich, England (52.5°N, 1°E) the cloud was a thin veil that was not always present. On most evenings when the sun was visible, a round area of diffused pale bluish-white light appeared around the sun, extending 20-30° out from it and remaining obvious after sunset. On 28 and 29 May a brownish band appeared around the perimeter of the bright area, separating it from blue sky; this was interpreted as Bishop's Ring. A similar ring and a prominent sun pillar were noted around the midnight sun on 13 June at latitude 67.5°N between Bodí and the Lofoten Islands, Norway.

Observations from Australia, Samoa, and New Zealand. This report is from John Gras and Keith Bigg.

"At Sydney, Australia (33.77°S, 151.1°E) brilliant sunsets have been observed consistently since 17 June until present (21 July). Twilight intensity measured at 20° elevation was also greatly enhanced on 24 May, but had subsided on 30 May increasing again by 17 June. Shadow heights indicated layers at 15 and 25 km on 24 May and between 15 and 20 km subsequent to 17 June.

"Brilliant twilights were also observed at Samoa (14.28°S, 170.68°E) during a visit 19-29 June. Twilight intensity and shadow height on 27 June indicated a pronounced layer at 20 km.

"No enhancement of twilight was evident at New Plymouth, New Zealand (39°S, 174°E) 26 June-2 July."

Information Contacts: W. Fuller, NASA; M. Hirono, Kyushu Univ., Japan; H. Lamb, Univ. of East Anglia, England; John Gras and Keith Bigg, CSIRO Division of Cloud Physics, Australia.