Fluctuations of the Karaugom Glacier (North Ossetia–Alania) and Climate Change from the Early 18th to the first quarter of the 21st Centuries Based on Remote Sensing Data, Historical and Dendrochronological Sources

Abstract

The reconstruction of fluctuations of the Karaugom Glacier (North Ossetia — Alaniya) from the middle of the 18th century to the first quarter of the 21^st century is based on space images, cartographic materials from 1888, 1932, and 1958, as well as schemes created by various researchers in the late 19^th and 20^th centuries and archival photographs of the glacier’s forelands from the late 19th century. Based on these sources, six moraine complexes formed during the 18^th to 20^th centuries were identified. The maximum advance of the glacier during the Little Ice Age occurred before the second half of the 18th century, while the most pronounced lateral moraines were formed during the advance in the 1830s–1840s. Over the past three centuries, the glacier’s front has risen by 460 m in elevation and retreated approximately by 3.6 km. The local reconstruction of the variability of summer temperatures based on the Blue Intensity of pine tree rings reveals alternating multidecadal cycles of cold and warm periods with expressed warming in recent decades corresponding to the higher rates of glacier retreat in the first quarter of 21^st century.