Extreme Climatic Events in the Altai-Sayan Region as an Indicator of Powerful Volcanic Eruptions

• Published in: Izvestiya. Atmospheric and oceanic physics Vol. 54; no. 10; pp. 1449 - 1459
• Main Authors: Barinov, V. V., Myglan, V. S., Taynik, A. V., Oidupaa, O. Ch, Agatova, A. R., Churakova (Sidorova), O. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.12.2018; Springer Nature B.V
• Subjects: Anomalies; Climatic extremes; Climatology; Colour; Earth and Environmental Science; Earth Sciences; Extreme cold; Extreme low temperatures; Forest management; Forest vegetation; Forests; Geophysics/Geodesy; Microscopic analysis; Mountain regions; Mountains; Ring structures; Stratosphere; Stratospheric aerosols; Tree rings; Trees; Volcanic activity; Volcanic eruptions; Volcanoes; dendrochronology; missing rings; volcanic eruptions; temperature anomalies; climatic extremes; the Altai-Sayan Mountain Region; light rings; frost rings; changes in annual ring density
• ISSN: 0001-4338; 1555-628X
• DOI: 10.1134/S000143381810002X

— Analytic data on anomalies of the tree-ring structure of Siberian larch on the transect, passing through the Russian part of the Altai-Sayan Mountain Region from the west to the east along the top forest limit, are given for the first time. Four extreme events (1783–1785, 1788–1789, 1812–1814, and 1884) have been determined by a microscopic analysis of the anatomic structure of tree rings (identification of frost, light-colored, and missing rings and fluctuations in wood density). These were periods of strong cooling in almost the entire area of the Altai-Sayan Mountain Region. The data correspond to archived historical materials. A comparison of dates of extreme cold periods with data on volcanic eruptions, the emissions of which reached the stratosphere (the Volcanic Explosivity Index VEI ≥ 4), has shown that they coincide with periods of the awakening of volcanoes such as Laki (1783, VEI = 4), Asama (1783, VEI = 4), Etna (1787, VEI = 4), Soufriere (1812, VEI = 4), Awu (1812, VEI = 4), Suvanosedzima (1813, VEI = 4), and Krakatau (1883, VEI = 6). Nevertheless, the trees in the studied area did not respond to the large eruptions of the Tambora (1815, VEI = 7), Novarupta (1912, VEI = 6), and Pinatubo (1991, VEI = 6) volcanoes. This difference in the reaction of forest vegetation to strong volcanic eruptions of the 19th–20th centuries may be explained by changes in the direction and speed of atmospheric streams, the mosaic pattern of stratospheric aerosols in the north of Central Asia after the eruptions of some volcanoes, and the warmer climate in the 20th century (which reduced the sensitivity of trees at the top forest line in the Altai-Sayan Mountain Region to volcanic eruptions due to the upward shift of the temperature limit of forest development).