Vol 43, No 6 (2018)

The paper analyzes the results ofthe numerical experiment aiming at the reconstruction of climate ofthe penultimate (Eemian) interglacial (last interglacial, LIG) obtained using the Earth system model developed in the Institute of Numerical Mathematics of RAS. Orbital parameters were set with the periodicity of one thousand years and were further interpolated with the time step of 100 years. Assuming that during the LIG the concentrations of greenhouse gases were not very much different from the preindustrial values, this potential forcing was neglected. The climatic block of the ESM was called every 100 model years to foltow changes in orbital forcmg. The sub–models of ice sheets were asynchronously coupled to the sub–models of the atmosphere and the ocean with the ratio of model years as 100 to 1. Obtained anomaly (Eemian versus preindustrial) fields of surface air temperature generally correspond to the results of the earlier studies. Changes in the structure of the global atmospheric circulation resulted in the transformation ofthe precipitation field in some world regions. In particular, precipitation growth in North Africa was the reason for the radical change of landscapes.

The features of changes and variability for cold temperature extremes over Russia are analyzed using observational data for the period from the middle of the 20th century. The impact is assessed that observed changes in thermal regime make on the characteristics of rare extremes which are used as standard parameters for designing infrastructure facilities. The results are interpreted in terms of the power system operation reliability. The risk assessment for critical temperature impacts indicates the important regional features of climate change effect on extreme energy loads and requirements for power capacities during the cold season.

Changes are considered in the runoff regime of Russian rivers and in the water inflow to reservoirs as a result of the climate warming observed in the country since the second half of the 1970s. Based on the analysis of long–term observational data on water inflow to 41 large reservoirs with the volume of 10 x 10⁶ m³, it is shown that considerable changes in its intraannual distribution have occurred in the recent decades. These changes are characterized, in particular, by the inflow increase during the cold season and by the runoff variability increasing in winter and summer–autumn seasons. The growth of the number of severe hydrological events, especially of flash floods induced by rainfalls, has been registered in the recent decades. Potential future changes in water inflow to reservoirs are considered in accordance with the scenarios of further climate warming. It is justified that rules of using water resources of reservoirs should be corrected taking into account the observed changes in the river water inflow regime.

The applicability is analyzed of the modeling system consisting of the MGO regional climate model and multilevel atmospheric boundary layer model for the mesoscale climate change evaluation in the regions with irrigated land use. Based on these models, the Aral Sea evolution impact on the spatial distribution of temperature and humidity in the vicinity of irrigated land is assessed. Numerical experiments cover climate evolution during 1979–2011. It is shown that in the middle of the 20th century the Aral Sea impact was manifested in the temperature and humidity distributions up to the altitude of 200–300 m at the distance of about 40 km off the seashore. The effect of advection on the calculated values of evapotranspiration in irrigated areas located at different distances from the sea is also investigated. Different methods for the determination of evapotranspiration over the irrigated cotton fields are intercompared. The influence of different resolution of surface temperature distribution on total evapotranspiration estimates is analyzed.

An attempt is made to identify the response of forest stands to recent climate change in the north of the European part of Russia using the series of Scots pine linear increments. These series are a useful instrument for assessing the spatial variability of internode growth parameters during short (to 30 years) periods. Linear dendrochronological data allow separating climatogenic reactions of organisms from the interannual variability of increments. In other words, this method allows reducing the level of noise which masks the sought dependences.