September 7 morning observations of Anak Krakatau put the lower ash layer up to 4.57 km high and moving west. BMKG reports a speed of 15 knots in that layer. Higher ash is observed farther west and southwest over the Indian Ocean. Its offshore movement still affects flights, while no significant change in extent or intensity was reported against the immediately preceding observation.
Anak Krakatau’s lower ash layer was moving west in the observations reported on September 7. Indonesia’s meteorology, climatology and geophysics agency BMKG put this layer up to 4.57 km high, travelling at 15 knots. The agency’s SIGMET bulletin, which describes weather hazards affecting aviation, covered 06:30–09:30 western Indonesian time and described consistent ash intensity in that layer.[1], [2]
Higher ash, extending up to 15.24 km, was observed farther offshore over the Indian Ocean. BMKG placed it west and southwest of Bengkulu, Lampung and Banten. Images from Himawari-9 taken at 09:00 western Indonesian time showed winds generally carrying ash westward. The assessment reported by Bisnis.com said the high-altitude ash continued to affect flights even as it moved farther out over the ocean.[1], [2]
The latest assessment reported by Bisnis.com found no significant change in ash extent or intensity against the immediately preceding observation. BMKG also reported that a paper test carried out at 07:00 western Indonesian time confirmed ash at several airports.[1], [2]
