Climate Changes in Western European Russia in the Late Holocene

Data on past climate changes can serve as the basis for the analysis of its modern trends and the forecast of future ones. A large number of studies were dedicated to the reconstruction of climate changes. Nonetheless, some spatial and temporal aspects of this problem still remain crucial. For instance, chronological boundaries of many paleoclimatic events during the last millennium remain unclear. Data on some climatically and historically important areas such as the western European part of Russia (EPR) are still insufficient. The peat section in the central part of the Usvyatskii Mokh bog serves as one of the objects for long-term stationary studies of the western Dvina forest‐bog station of the Institute of Forest Science, Russian Academy of Sciences (western Dvina area of the Tver district, (56 ° N, 32 ° E). The study of this section provided data for the adequate reconstruction of climatic conditions of the western part of the EPR. Simultaneously, they made possible more accurate estimates of temporal boundaries of main paleoclimatic events in the Late Holocene. Favorable conditions in January 1999 for peat excavation (extremely low temperature and absence of snow) allowed us to penetrate the peat section to a depth of 80 cm by making a prospecting pit and then to a depth of 2 m using the TBO peat corer. The section was sampled for a palynological study with steps of 1 and 2.5 cm. In total, 128 samples were studied. Paleoclimatic reconstructions were performed based on palynological data (determinations by E.S. Malyasova) and using the information statistical method. Radiocarbon dates for 20 samples of peat and buried wood were obtained at the Geological Institute of the RAS in the laboratory headed by L.D. Sulerzhitskii. Calendar dates were obtained using the last version of the CALIB program [1]. Data from instrumental meteorological observations at the Riga, St. Petersburg, Moscow, and Vilnius stations, as well as paleoclimatic materials provided by historical sources for the western part of Eastern Europe [2], were used for calibration and verification of the results. The reconstructed pattern of climate change (Fig. 1) is considered based on the Blitt‐Sernander Holocene Scale modified by Khotinskii [3]. The values of climatic parameters are given as deviations from their modern values determined here as a norm for the 1951‐ 1980 period: the average temperature for July and January was about 16.5 ° C and ‐8 ° C, respectively: the annual average temperature was about 4.5 ° C, and total precipitation was about 700 mm.