Search

The tundra was divided into different classes depending on the temperature and precipitation in accordance with the Holdridge classification. Dry, moist, wet, and rainy tundras were distinguished. Datasets on climate variability were obtained from the Climatic Research Unit website (http://www.cru.uea.ac.uk/data) for the period from 2001 to 2017. The long-term (2001–2016) dynamics of phytomass for different tundra classes was studied on the basis of the Normalized Differential Vegetation Index (NDVI). The positive long-term dynamics of NDVI-vegetation for the tundra classes studied was revealed. This trend correlates with the positive dynamics of the mean annual biotemperature. It was shown that the impact of global climate change on vegetation of different tundra classes is ambiguous. For the dry tundra, the increase in NDVI in May and June was higher than for the rainy tundra. This correlates with the fact that the increase in the mean monthly temperatures in May and June on the territory of the dry tundra is greater than on the territory of the rainy tundra. [ABSTRACT FROM AUTHOR]

Scanning micro-X-ray fluorescence analysis with synchrotron radiation was applied to obtain the depth-variation profiles of element compositions of banded clays in Peyungda Lake (Krasnoyarsk krai, Evenkia) located 30 km southwest of the epicenter of the Tunguska event (1908). The age model was confirmed by a dated layer of anomalous thickness related to the fall and explosion of the Tunguska Cosmic Body (TCB). The variations in the element content in dated core layers were compared with the instrumental meteorological observation data over the last century. The regional average annual temperature and element compositions of the coeval bottom sediments (transfer function) were found to be interrelated. The approximation of the transfer function to the sampling depth of the sedimentary section made it possible to reconstruct the air temperature in the studied region over the past 1000 years. The average annual temperature reconstructions in the study area compared with the global temperature reconstructions in the Arctic region for the same period made it possible to reveal general trends and extreme values. [ABSTRACT FROM AUTHOR]