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The spatial and temporal variability of the main climatic indicators on the territory of the Volga Federal District in the 20th–21st centuries is considered. A general increasing trend in air temperature is revealed, and a heterogeneous pattern of precipitation changes is shown. The temperature variations until the end of the 21st century are analyzed on the example of Kazan using 40 CMIP6 climate models for four anthropogenic scenarios. In the paper, there is an assessment of the dynamics of agroclimatic resources on the territory of the Volga Federal District: the duration of the growing season, the sum of positive temperatures, total precipitation, and photosynthetic radiation. A correlation has been found between the temperature fluctuations in the region and the atmospheric circulation indices (NAO, AO, SCAND, and EAWR). For the territory of Tatarstan, a degree of aridity and waterlogging is evaluated using the agroclimatic indices: the Budyko's dryness index, the Selyaninov's hydrothermal coefficient, the Sapozhnikova's moisture index. It is shown that there is a tendency toward an increase in the duration of the growing season, its heat supply and aridity in the region in summer. A statistical estimation of the dependence of spring wheat yield on the agroclimatic indices on the territory of the Republic of Tatarstan is given. [ABSTRACT FROM AUTHOR]

The overview of papers dealing with the analysis of current and future climate change on the territory of Russia and their impact on the crop productivity is presented. Using the reanalysis data for 1950–2020, trends in air temperature and precipitation are estimated for different regions of Russia. A correlation was found between changes in temperature and atmospheric circulation indices. [ABSTRACT FROM AUTHOR]

The paper presents the results of the verification of ERA-Interim and ERA5 reanalyses data on surface air temperature obtained from drifting buoys, ground-based weather stations, and, for the first time, from measurements at the North Pole drifting stations. The North Pole station data were not assimilated in the reanalyses, which provides a rare opportunity for independent validation. The comparison with data of the North Pole drifting stations revealed that bias for the cold season in the Arctic basin is 2.25°С for ERA-Interim and 3.92°С for ERA5, respectively. The comparison with data of drifting buoys allows us to speculate about the cause of such large errors in the reanalyses. Some buoys were installed from the air-based platform. In this case, the temperature sensor of the buoy was potentially buried in the snow cover that shielded it from the cold atmosphere and contributed to the heating due to the heat flux from the underlying layer of sea water. The assimilation of such data could be one of the reasons for the overestimation of air temperature over drifting ice in the both reanalysis. [ABSTRACT FROM AUTHOR]

The description of the ocean-atmosphere coupling is presented. The paper analyzes the data of MERRA, JRA, ERA-Interim, and ERA-20Century reanalyses and the re suits of CCM chemistry-climate model simulations based on monthly mean values of air temperature and ozone mixing ratio at the levels of 925 and 20 hPa during 1980–2015. The comparison with data on sea surface temperature is provided. The results of simula-ion are in good agreement with reanalysis data for the atmospheric surface layer, whereas essential differences for the stratosphere require a more detailed analysis. According to the model results, air temperature rises in the surface layer, and air temperature and ozone mixing ratio decrease in the stratosphere. Reanalysis data do not coniradict simuiaiion results for the troposphere but differ significantly for the stratosphere. [ABSTRACT FROM AUTHOR]

Observed climate change leads to the variations in the phenology, physiology, and biochemistry of grape berries, to a shift in the distribution of the grape plant areas and, as a result, to a change in the specialization of associated regions. Using the agroclimatic indicators for a comprehensive assessment of the climate change impact on viticulture, a comprehensive assessment of the grape growth conditions, potential quality of wine, and the climate-related risks in the Crimea and Donbass (on the example of Sevastopol and Artemovsk) over two 30-year periods (1961–1990 and 1991–2020) has been carried out. The results have shown a significant change in climatic conditions: an increase in heat availability in both regions and a decrease in frost susceptibility in the south of Donbass. [ABSTRACT FROM AUTHOR]

For large-scale heat waves that occur in the south of the European part of Russia (EPR), the frequency variability since the beginning of the 20th century is considered, including variations on decadal scales and a trend during the global warming period, accompanying variations in the aridity index SPI, and the structure of the longest waves. The geographic distribution of air temperature anomalies on the territory of the Russian Federation, large-scale circulation conditions, the North Atlantic sea surface temperature (SST) anomalies, which accompanied heat waves in the south of the EPR, are analyzed using the composite analysis. In particular, the wave structure was revealed of the composite field of the air temperature anomaly for days with heat waves and the related 500 hPa geopotential height () fields over Russia. The field structure generally corresponds to the negative phase of the East Atlantic–Western Russia (EAWR) circulation pattern. Similar structures of the geopotential field are observed during heat waves in the northern half of the EPR. However, in this case, there are specific features that contribute to the inflow of cold air from the north to the southern regions. It is shown that the values of the EAWR index are significantly shifted towards negative values in the months when long heat waves occur over the southern EPR. The waves are accompanied by positive anomalies of the North Atlantic SST and the strongly increased blocking anticyclone activity. The downward trend in the EAWR index observed in recent decades and the SST rise expected with the global warming increase a risk of droughts in the main grain-producing region of the country. [ABSTRACT FROM AUTHOR]

Extreme temperature events and their long-term variability are investigated using daily air temperature data from Murmansk weather station for the period of 1942–2018. It was found that the variability of extremely warm and cold events in Murmansk in winter is mainly explained rather by the dynamics of storm tracks than by the local processes of air mass transformation in the region. It is shown that the main characteristics of extreme events demonstrate a clearly pronounced seasonality. It was revealed that the positive trend in seasonal mean temperatures is mainly due to the reduced number of extremely cold events in Murmansk. The study shows that the leading factor determining the variability of extreme events is the Arctic Oscillation (AO). In turn, the AO anomalies are formed as a result of the dynamic stratosphere–troposphere coupling, which is expressed in the response of storm tracks to sudden stratospheric warmings. [ABSTRACT FROM AUTHOR]

The spatiotemporal variability of surface air temperature and precipitation in Russia is considered using the data from 1251 stations for two periods: 1976–2019 and 2001–2019. Main attention is paid to the analysis of trends in the above characteristics, which made it possible to estimate the scale of climate warming in recent decades. The connection between the atmospheric circulation indices (NAO, AO, EAWR, SCAND) and temperature fluctuations in the European part of Russia is revealed. [ABSTRACT FROM AUTHOR]

Uncertainty in predicted precipitation and air temperature are the main sources of the uncertainty in flood forecasting. In this study, the fuzzy set theory is used for assessment of impact that uncertainty in precipitation and air temperature data has on flood forecasting in the Dez basin in southwestern Iran. The precipitation and air temperature were predicted using the Weather Research and Forecasting (WRF) model. The results showed that the uncertainty in peak discharge and flood hydrograph volume was considerably higher due to uncertainty in the precipitation than in air temperature. It was observed that the uncertainty of the peak discharge due to the 10% uncertainty in precipitation and air temperature is 14.8% and 5.6%, respectively. Also, the uncertainty of the flood hydrograph volume due to the 10% uncertainty in precipitation and air temperature is 13.1% and 4.6%, respectively. Therefore, to reduce uncertainty in peak discharge and flood hydrograph volume, precipitation should be predicted more precisely than air temperature. [ABSTRACT FROM AUTHOR]

The study analyzes modern climate change based on the data of the climate monitoring performed by the Izrael Institute of Global Climate and Ecology. A brief description of the surface climate monitoring database and its real-time updating is given. Changes in surface temperature over the Earth's land with detailing over the territory of Russia and its regions, as well as changes in the precipitation regime in Russia during the period of modern warming are considered. Changes in the statistics of temperature extremes in Russia are analyzed. Some extreme summer seasons are characterized in terms of accompanying their circulation conditions. [ABSTRACT FROM AUTHOR]

The thermohaline structure of water in the Antarctic coastal areas adjoining Molodezhnaya, Novolazarevskaya, and Bellingshausen stations is analyzed using many-hour soundings carried out in March–April 2019 during the 64th Russian Antarctic Expedition on the Akademik Fedorov research vessel. Water masses typical of the Antarctic zone (Antarctic surface, Antarctic shelf, Antarctic winter, upper circumpolar deep water, Bransfield Strait surface water) are identified, and the features of their temporal variability are described. It is shown that intradaily and interdaily variations in water temperature and salinity were observed during the measurement period. The changes in the water structure in the area of Molodezhnaya, Novolazarevskaya, and Bellingshausen stations occurred under changes in synoptic atmospheric conditions, and their frequency was close to that of tidal processes. [ABSTRACT FROM AUTHOR]

Some aspects of long-term variability of temperature extremes on the territory of Russia are considered using average daily surface air temperature data from 367 weather stations over the period of 1960-2016. The number of days with extremely high summer temperature has increased monotonously (with strong peaks in some years) in the European part of Russia since the 1980s; in the Asian part of Russia this growth stopped in the early 2000s. The number of cold extremes has decreased. Changes in winter mainly agree with the general warming, but in the Asian part of Russia the warming trend is superimposed by about 40-year oscillations resembling variations in the leading atmospheric circulation modes: the North Atlantic Oscillation (NAO) and the Scandinavian pattern. The statistics of indices of extremes in the opposite phases of the modes revealed a strong response in winter, which explains qualitatively the features of long-term variations in temperature extremes. A difference in composites between the positive and negative NAO phases is mostly negative for cold extremes and positive for warm ones. The response to the Scandinavian mode is opposite. In summer, the response is generally weak, but in the west of the European part of Russia the heat wave duration is strongly linked to variations in the Scandinavian pattern. [ABSTRACT FROM AUTHOR]

The characteristics of spatiotemporal variability of air temperature and ozone mass mixing ratio at 26 levels from the ground to the altitude of 64 km are considered using the ERA-Interim reanalysis data for 1979–2016. Differences are revealed in the distribution of air temperature trends between seasons and latitude zones, between the Atlantic-European, Asian-Pacific, and American sectors of the Northern Hemisphere mid-latitudes, and between the thermal regime over the land and ocean. The correlations between the layers and atmospheric circulation patterns in different seasons are assessed. [ABSTRACT FROM AUTHOR]

The statistical scheme is proposed for the forecast of surface air temperature and humidity using operative weather forecasts with 3-5-day lead time from the best forecasting hydrodynamic models as well as the archives of forecasts of these models and observational data from 2800 weather stations of Russia, Eastern Europe, and Central Asia. The output of the scheme includes the forecasts of air temperature for the standard observation moments with the period of 6 hours and extreme temperatures with the lead times of 12-120 hours. The accuracy of temperature and humidity forecasts for the period from July 2014 till June 2017 is much higher than that for the forecasts of original hydrodynamic models. The skill scores for extreme temperature forecasts based on the proposed method are compared with the similar results of the Weather Element Computation (WEC) forecasting scheme and forecasts by weathermen. [ABSTRACT FROM AUTHOR]

The dependence of energy consumption on air temperature for every day of the period from 1990 to 2015 is for the first time studied for mid-latitudes using the long-term observational data of the Moscow State University Meteorological Observatory. It is demonstrated that this dependence is generally descending in the Moscow region: energy consumption decreases as air temperature rises. At the same time, the energy consumption increase slows down due to energy saving in case of severe frosts, whereas the opposite trend is manifested in case of abnormally hot weather, that is, the energy consumption increase along with the air temperature rise due to additional consumption for air conditioning. The optimum temperature for energy saving is 18°C. The relationship between energy consumption and air humidity characteristics is analyzed. There is almost no link with relative humidity, while in the link with the partial pressure of water vapor, the dependence of the latter on air temperature is reflected indirectly. [ABSTRACT FROM AUTHOR]

The method is proposed for assessing the wintering conditions of winter crops with the accuracy to separate sown areas based on the joint use of the data of remote sensing and ground-based observations. The dependence is revealed between snow depth and snow albedo in the red band (MOD09GQ data). Geoinformation mapping of wintering conditions of winter crops cultivated in the Belgorod oblast is carried out for the winter period of 2012/2013. [ABSTRACT FROM AUTHOR]

The variations in average annual surface air temperature, precipitation, and runoff in the Selenga River basin (within Russia) are analyzed. It is demonstrated that the considerable increase in average annual temperature of surface air layers occurred in the 1980s-1990s. The decrease in peak water discharge in the rivers and the increase in the frequency of low-water periods were revealed in the forest-steppe and steppe zones of the Selenga River basin in 2001-2010. In the southwestern mountain regions (the Dzhida River basin) the river runoff increased during that period. [ABSTRACT FROM AUTHOR]

Presented is the review of the modern knowledge of the Arctic Oscillation (AO). Demonstrated is the relation of air temperature and precipitation in Northern Eurasia to this dominant type of wintertime atmospheric variability at northern extratropical latitudes. It is demonstrated that AO is a result of the coupling between the troposphere and stratosphere. The attention is paid to the long-range forecasting of AO index and to the factors complicating the forecasting. Given are the new results of the authors' research. Used is the wintertime AO index computed by the authors from the 20th Century Reanalysis dataset. The high- and low-frequency components of AO index variability and the periods of statistically significant trends are analyzed using the 112-year series (1901-2012). Demonstrated is the key impact of wintertime AO phase on the anomalies of air temperature and precipitation in Northern Eurasia at the time scale of years and decades. This impact is manifested in the northern part of Northern Eurasia in the prevalence of warmer and wetter winters at the positive AO phase and of colder and drier winters at the negative AO phase. The precipitation anomalies of opposite sign prevail in the southern part of Northern Eurasia. It is demonstrated that the winter AO phase affects the terms of the springtime air temperature transition to positive values. [ABSTRACT FROM AUTHOR]