Adapting a model of heat and mass exchange between a water body and the atmosphere taking into account the effect of shallows: Case study of the Ivankovo Reservoir

The paper is based on a box model of heat and mass exchange with the incorporation of a block for calculating latent heat flux, supplemented by parameterization of heat and mass exchange between shallow water area and the atmosphere. The results of calculation of evaporation from the water area of the Ivankovo Reservoir, with allowance made for more intense evaporation from shallows, are given. The latent heat fluxes from shallow and deep-water zones of the water body are shown to differ, depending on weather conditions and water level; the increase in the evaporated-water volume due to taking into account the shallow-water effect is evaluated.     

On correlation between seismic velocity anisotropy and stressesin situ

Seismic velocity anisotropies measured in underground mines are compared within situ stress measurements in these mines. These underground data are also compared with seismic velocity anisotropies observed by large scale seismic sounding conducted from the earth's surface, The velocity anisotropies are about 10% and the data obtained by different methods on different scales and frequencies agree with each other. The directions of largest and smallest velocities coincide with the largest and smallest horizontal stresses, respectively. These results suggest that the direction and magnitude of stresses in potential mining areas could be estimated from velocity anisotropies observed in seismic prospecting of the area.     

Evaporation and heat exchange of a body of water with the atmosphere in a shallow zone

Results are rported from experimental and theoretical studies of the energy and mass exchange of a body of water with the atmosphere. A new parametric model has been developed on the basis of experimental data that takes into account the influence of the depth of the basin on evaporation, its heat exchange with the atmosphere, and the water-surface friction at different wind speeds. Comparison of the model with measurements during the LITFASS-98 and LITFASS-2003 experiments (Germany) shows good consistency. The results indicate, on the one hand, that the depth of the basin has a large effect on the intensity of energy exchange under natural conditions. On the other hand, the examples shown in the paper illustrate good agreement of the model calculations with experimental data. On the basis of the experimental data on the influence of the basin depth on the intensity of the interaction between the basin and the atmosphere, a balance model of the energy exchange in the coastal zone has been developed. The balance model calculates the momentum, heat, and moisture fluxes at different distances from the shore. Results of using the new model to estimate the intensification of evaporation and the heat exchange of the northern Caspian and the Kara-Bogaz Gol are discussed.     

Analysis of variations in the regime of rivers and lakes in the Upper Volga and Upper Zapadnaya Dvina based on archaeological-geomorphological data

The geomorphological and altitudinal positions of occupational layers corresponding to 1224 colonization epochs at 870 archaeological sites in river valleys and lake depressions in southwestern Tver province. A series of alternating low-water (low levels of seasonal peaks, many-year periods without inundation of floodplains) and high-water (high spring floods, regular inundation of floodplains) intervals of various hierarchical rank was identified. In low-water epoch, an increase was recorded in the share of settlements on low elevations, including river and lake floodplains now subject to inundation. The archaeological epochs 2–3 Ky in length were found to form the following series from high-water to low-water: Mesolithic (11.8–8.0 Ky ago)-Iron age (2.8–0.3)-Neolithic (8.0–5.0)-Bronze epoch (5.0–2.8). The first half of the Iron age (2.8–1.8 Ky ago) was extremely water-abundant, while its second half (middle ages) was dry (relative to the present time). A correlation between the hydrological and temperature regimes was identified: low-water epochs closely correlate with warm epochs, while high-water ones correlate with cold epochs. This can be associated with the specific features of the present-day type of water regime with dominating spring flood; this regime is supposed to have existed during the most part of the Holocene: the runoff and the levels of floods decline during warming epochs and increase during cooling epochs.     

Specific features of the hydrological regime of the Tsimlyansk Reservoir under climate changes in the Don basin

This study is a continuation of a cycle of studies into the effect of Atlantic climate on the hydrometeorological regime of European Russia. In this article, an attempt is made to analyze the effect of climate variations in the Atlantic on the Don basin and the hydrological regime of the Tsimlyansk Reservoir. A new composite index of heat transfer NAAII (North Atlantic Air Interaction Index) is suggested, the use of which enables the explanation of changes that have taken place in the Don basin. Evaporation was evaluated with the bathymetry of the Tsimlyansk Reservoir taken into account, and the water level of 32 m abs. was shown to be critical in the interaction between the reservoir and the atmosphere.     

Reconstruction of Late Pleistocene events in the periglacial area in the southern part of the East European Plain

An integrated study of the loess–soil sequence in the coastal exposure near the settlement of Beglitsa (Rostov oblast) allowed us, for the first time, to reconstruct the landscape-climatic changes that occurred in the eastern Azov region over the course of the Late Pleistocene. In the south of the periglacial zone, considerable differences between intensity of the loess accumulation in the Early and Late Valdai Cryochrons were revealed. In the Early Valdai Epoch, which corresponds roughly to the end of Marine Isotope Stage (MIS) 5 and MIS 4, loess accumulation occurred after completion of development of the Mezin pedocomplex and before the beginning of the Bryansk stage of soil development, i.e., over more than 20 000 years. In the much shorter Late Valdai Cryochron MIS 2 (10 000–12 000 years), loess accumulation reached 5 m. The data evaluation shows that the loess accumulation rates in the Early Valdai Epoch (~0.07 mm/year) and the Late Valdai Epoch (~0.5 mm/year) differ from each other by an order of magnitude.     

On the correlation between oscillations of the Caspian Sea level and the North Atlantic climate

Correlations between the changes in the climate of the Caspian Sea region and in its level and the variations in the North Atlantic climate are studied. The indices of North Atlantic oscillation (NAO), Atlantic multidecadal oscillation (AMO), the intensity of Atlantic thermohaline circulation (ATHC), and the air humidity above the North Atlantic are used as basic indicators of climatic variations that influence the Caspian Sea. Results of an experiment for reproducing the World Ocean circulation and the parameterization of cyclic climate peculiarities made it possible to reveal their impact on the formation of Eurasian climatic variability and on the level regime of the Caspian Sea. This impact is studied through the variability of ATHC, the NAO index, and a composite index of moisture transport (CIMT) that is proposed as a result of the studies.     

Present-day variations and paleodynamics of the Caspian Sea level as a standard for climate modeling data verification

Long-term variations of the Caspian Sea level occur mainly due to river runoff variations (the variations of the Volga River runoff is of primary importance here). In this case, the observed and reconstructed variations of the Caspian Sea level can serve as a standard for assessing the quality of the model runoff simulated by climate models. To solve this problem, a number of detailed maps of the Caspian Sea are prepared for the series of regression and transgression stages. These data are used for verifying the results of some numerical experiments carried out within the framework of CMIP5/PMIP3. It is demonstrated that the model data can be verified depending on how well the models simulate the present-day (instrumentally observed) variations of the decadal scale reconstructed in recent 1000 years of variations: the transition from the Derbent regression to the New Caspian transgression (the 5th phase) with the insignificant sea level drop in the late 19th century and under conditions of large regression during the period of the late Pleistocene glaciation maximum.     

Variations in wind direction and speed from arctic to the Caspian Sea as a manifestation of modern climate changes

The regularities in present-day variations in the wind speed vector are examined at 18 stations along the section from Kola Peninsula to the Caspian Sea. Data on long-term variations in the major climate-forming factors and climatic parameters are generalized. The statistically significant tendency toward a considerable decline in the wind speed with a maximum module and the most frequent wind speeds of zonal, mostly western, directions (this tendency has been revealed earlier for the eastern coast of the middle and southern Caspian Sea) was found to hold for the greater part of the European Russia. Possible causes of present-day climate changes and their manifestations at the regional level are analyzed. A possible mechanism of present-day climate changes is proposed