Evaluation of the Atlantic Multidecadal Oscillation Impact on Large-Scale Atmospheric Circulation in the Atlantic Region in Summer

Doklady Earth Sciences - The influence of the Atlantic Multidecadal Oscillation (AMO) on large-scale atmospheric circulation in the Atlantic region in summer for the period of 1950–2015 is...     

On the Impact of Insufficient Atmospheric Moistening on the Low Annual Discharge of Large Rivers in European Russia

Water Resources - The regional peculiarities of annual atmospheric moistening in European Russia are investigated using Standardized Precipitation and Evapotranspiration Index (SPEI). It was found...     

A link between winter precipitation in Europe and the Arctic Sea ice,sea surface temperature,and atmospheric circulation

The spatial and temporal pattern of the link between the winter precipitation variability and variations in the North Atlantic sea surface temperature, the Arctic sea ice concentration, and 500 hPa geopotential height in the Northern Hemisphere is analyzed for the period of 1952-2012. The analysis reveals two principal modes of covariability in the analyzed characteristics. The first mode which explains the most part of covariability, is related to the impact of the North Atlantic Oscillation. The second mode indicates the significant contribution of the Atlantic Multidecadal Oscillation associated with winter precipitation anomalies of the same sign in Europe with the maxima on the East European Plain and in the Balkan region during the positive phase of AMO.     

Model estimates of moistening conditions on the Russian plains by the middle of the 21st century

The spatiotemporal variations of long-term values of annual precipitation, annual radiation balance, and radiation index of dryness by the middle of the 21st century as compared with the last two decades of the 20th century were investigated using the results of numerical simulations based on the atmosphere-ocean general circulation models (AOGCMs). According to the model scenarios, the variations of moistening conditions follow the arid and arid-humid combined types. All models predict the significant moistening reduction in the south of European Russia by the middle of the 21st century. Studied is the reaction of boundaries of moistening zones in subboreal flat landscapes of Russia to the climate change. It is demonstrated that in spite of different directions of the spatial shift of moistening zone boundaries predicted by the climate models, these changes remain within the interannual selective variability.     

Reaction of boundaries of moistening zones of the Russian plains to the climate changes

Spatio-temporal moistening variations of subboreal plain landscapes of Russia and the reaction of boundaries of moistening zones to the climate changes as a whole are investigated for the period of 1936–2006 and for its certain intervals. The areas with homogeneous moistening variations and nonlinear moistening trends in every area are determined, coefficients are computed of linear trend of annual precipitation and evaporativity, of annual moistening, and of moistening for vegetation season on the whole territory. It is demonstrated that the boundaries of moistening zones of the territory for the period under consideration remained within the limits of interannual sample variability.     

The Kharamai kimberlite field, Siberia: modification of the lithospheric mantle by the Siberian Trap event

The kimberlites of the Kharamai field intruded through the Siberian Traps shortly after their eruption in Permo-Triassic time. The composition and thermal state of the subcontinental lithospheric mantle (SCLM) beneath the Kharamai field in lower Triassic time have been reconstructed using major- and trace-element analyses of 345 Cr-pyrope garnet xenocrysts from six of the kimberlites, supplemented by a small suite of mantle-derived peridotite xenoliths. The data define a geotherm lying near a 38 mW/m² conductive model to a depth of ca 170 km, where the base of the depleted lithosphere is defined by a marked increase in melt-related metasomatism and by an inflected geotherm. Compared to the SCLM sampled by Devonian (pre-Trap) kimberlites in the same and adjacent terranes, the Kharamai SCLM in Triassic time was warmer and was cooling from a previous thermal high. It was also thinner than the SCLM beneath the Daldyn and Alakit kimberlite fields, and had been strongly metasomatised. The metasomatism lowered the mean Fo content of olivine (from ≥Fo₉₃ to Fo₉₂), greatly reduced the proportion of subcalcic harzburgites, and increased the proportion of fertile lherzolites, especially in the depth range of 80–130 km. The overall pattern of metasomatism is similar to that observed in the SCLM sampled by the Group I kimberlites of the SW Kaapvaal Craton, and inferred to be related to the Karoo thermal event. These observations suggest that events such as the eruption of the Karoo basalts and Siberian Traps change the composition of the SCLM, but do not necessarily destroy it, at distances of several hundred kilometres from the main eruption centres.     

A New Approach to the Identifying of the Extreme Climate Effect on the Wheat Yield Reduction in the South of European Russia

Doklady Earth Sciences - The change in seasonal extreme climatic conditions driving low wheat yields in the South of European Russia in the period of 1991–2019 compared to 1961–1990 has...     

Dynamics of severe atmospheric droughts in European Russia

Severe atmospheric droughts of different intensity over the southern Russian Plain are studied using the observations and model data during the period of 1936–2100. Spatial distribution, frequency, and duration of droughts are considered. Dynamics of extreme droughts in the 20th century is derived from the meteorological station data. The tendency of drought occurrence in 1991–2000, 2041–2050, and 2091–2100 is obtained from the MGO (Main Geophysical Observatory) regional climate model (RCM). A catalog of severe atmospheric droughts of different intensity is made based on the observations for 1936–2000 and modeling results for 1991–2000. The comparison of the observational and model data has shown that the MGO RCM simulates well the frequency of severe atmospheric droughts.