Dendroclimatic reconstruction of late summer temperatures from upper treeline sites in Greater Caucasus, Russia

摘要

Recent evidence suggests an acceleration of the glacier retreat in the Greater Caucasus after 1980. A significant summer temperature warming trend and little or no change in precipitation variation have been observed during the same period. This study aims to find similar past climatic conditions after the Little Ice Age (LIA) using a dendroclimatic approach. A dendroclimatological sampling of Scots pines (Pinus sylvestris L.) has been made in Irik Valley, near Elbrus glacier. The dendroclimatic indexes (average sensitivity, PC1, and RBAR) indicate a medium response of the radial growth to the variation of the climatic factors. The July and August (JA) temperatures of the current year and May and June (MJ) temperatures of the previous year have a significant correlation with tree ring width. No significant correlation with precipitation has been noticed. A tree-ring width chronology has been used to reconstruct JulyeAugust (JA) temperatures back to 1830. The warming (during 1981-2009) is well preserved in our reconstructed JulyeAugust temperatures and seems to be an important warm sequence. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.