30-year lidar observations of the stratospheric aerosol layer state over Tomsk (Western Siberia

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Zuev, Vladimir V., Nevzorov, Aleksei V., Pravdin, Vladimir L., Savelieva, Ekaterina S., Gerasimov, Vladislav V., Burlakov, Vladimir D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Томск; город; лидарные наблюдения; стратосферный аэрозольный слой; Hampton; Eyjafjallajökull; Siberia
• Online Access: https://doi.org/10.5194/acp-17-3067-2017; http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000577244

There are only four lidar stations in the world which have almost continuously performed observations of the stratospheric aerosol layer (SAL) state over the last 30 years. The longest time series of the SAL lidar measurements have been accumulated at the Mauna Loa Observatory (Hawaii) since 1973 the NASA Langley Research Center (Hampton Virginia) since 1974 and Garmisch-Partenkirchen (Germany) since 1976. The fourth lidar station we present started to perform routine observations of the SAL parameters in Tomsk (56.48° N 85.05° E Western Siberia Russia) in 1986. In this paper we mainly focus on and discuss the stratospheric background period from 2000 to 2005 and the causes of the SAL perturbations over Tomsk in the 2006–2015 period. During the last decade volcanic aerosol plumes from tropical Mt. Manam Soufrière Hills Rabaul Merapi Nabro and Kelut and extratropical (northern) Mt. Okmok Kasatochi Redoubt Sarychev Peak Eyjafjallajökull and Grímsvötn were detected in the stratosphere over Tomsk. When it was possible we used the NOAA HYSPLIT trajectory model to assign aerosol layers observed over Tomsk to the corresponding volcanic eruptions. The trajectory analysis highlighted some surprising results. For example in the cases of the Okmok Kasatochi and Eyjafjallajökull eruptions the HYSPLIT air mass backward trajectories started from altitudes of aerosol layers detected over Tomsk with a lidar passed over these volcanoes on their eruption days at altitudes higher than the maximum plume altitudes given by the Smithsonian Institution Global Volcanism Program. An explanation of these facts is suggested. The role of both tropical and northern volcanic eruptions in volcanogenic aerosol loading of the midlatitude stratosphere is also discussed. In addition to volcanoes we considered other possible causes of the SAL perturbations over Tomsk i.e. the polar stratospheric cloud (PSC) events and smoke plumes from strong forest fires. At least two PSC events were detected in 1995 and 2007. We also make an assumption that the Kelut volcanic eruption (Indonesia February 2014) could be the cause of the SAL perturbations over Tomsk during the first quarter of 2015.