Volcanic aerosol layer formed in the tropical upper troposphere by the eruption of Mt. Merapi, Java, in November 2010 observed by the spaceborne lidar CALIOP

•Global distribution of the upper tropospheric volcanic clouds is reported by using the data by CALIOP.•It is proved the eruption of Mt. Merapi in November 2010 is the source of the volcanic clouds found by ground-based lidar.•The total amount of the volcanic clouds is estimated, and is compared with the total amount of SO2.•Change in the appearance frequency of cirrus clouds synchronizing with the volcanic clouds is not detectable in this case.

Mt. Merapi in Java, Indonesia, erupted in November 2010. The eruption was proved to be the source of the aerosol layer observed by a ground-based lidar at Biak, Indonesia, in January 2011 using data on the global distribution of aerosols observed by the spaceborne cloud-aerosol lidar with orthogonal polarization (CALIOP). These data were used to describe how the volcanic aerosols produced by the volcanic eruption diffused throughout the tropical tropopause layer (TTL). The equivalent maximum total amount of volcanic SO2 estimated from the spatially integrated total amount of aerosols was 0.09 Tg, which is one-third to half that of gaseous SO2 after the eruption was observed by the ozone monitoring instrument satellite. The obtained cirrus-cloud-appearance frequency data exhibit a seasonal cycle having its maximum in winter and no detectable variations that are synchronized with the increase in TTL volcanic aerosols.