Том 44, № 7 (2019)

The study considers the problem of detailing climate projections with respect to changes in the precipitation regime over the territory of Russia by the middle of the 21st century. Numerous ensemble calculations with the high-resolution regional climate model are used to obtain the projections of climatic changes concerning the duration of dry and wet spells as well as in the related extremes of the amount and daily intensity of precipitation. The estimates of the trend in the analyzed precipitation characteristics derived from standard meteorological observations are presented for 1966–2015. Important seasonal and regional features of changes in the analyzed parameters of extremity are revealed. It is reasonable to consider these features when adapting to climate change at the regional level.

A method for analyzing the variability of characteristics of different cloud types is developed using the results of cloud classification and thematic processing of satellite data. To increase the efficiency of the proposed approach, 16 cloud types were identified during the periods of snow cover absence, and 12 cloud types, in its presence; parallel computation methods on the general-purpose graphic processor units were used. The results of studying the frequency of various cloud types and variations in their parameters over the latitude zones of 50°–60° and 60°–70° N in the Tomsk oblast in 2017 are analyzed. The episodes with the deviation from the annual course are considered for a number of characteristics of several cloud types.

The main characteristics of water masses in the Laptev Sea formed as a result of the mixing of Atlantic and river water and transformed as a result of ice formation and ice melting were revealed using the conservative isotopic parameter δ¹⁸O as a tracer. The amount of Atlantic, river, and melt water as well as the volumes of water withdrawn for ice formation are quantified for six water masses typical of the Laptev Sea. Both melt and transformed (as a result of ice formation) water types are present in the surface river water mass. The prevalence of melt water is observed in the range of sea water salinity from 0 to 7–8 psu. The maximum content of melt water in this salinity range can reach 40%, and the desalination resulting from ice melting reaches 0.2–0.7 psu. The areas with the maximum water removal for ice formation are linked to the position of summer and winter water of the Laptev Sea, in the area of the Anabar-Lena, East Taymyr, West New Siberian, and North New Siberian flaw polynyas and fast ice in the southeastern part of the sea. In these regions water removal for ice formation makes up 10 to 20% and is observed from the surface to the bottom even during the summer-autumn period. Atlantic water is characterized not only by mixing with river water from Siberian rivers but also by transformations resulting from ice formation. However, this effect is largely associated with the convective mixing with overlying layers where ice formation occurs. Mean temperature of the bottom layers of Arctic basin water is by 2.2°C lower than the mean temperature of Atlantic water, and mean salinity is by ~0.06 psu higher. In this water the presence of river water as well as the influence of ice formation and ice melting mass are less pronounced as compared to Atlantic water.

The study considers problems of estimation of the areal reduction of flood-forming rainfalls based on the joint use of rain-gage and radar information for the territory of the Urals. Information on areal rainfall reduction is crucial in development of methods for calculating the flood runoff of unexplored rivers. The large volume of rain-gage records (>6000 individual showers) for the period of 1936–2015 was collected and processed as well as radar data on cloud reflectivity for the period of 2003–2015 (data of the MRL-5 pulse weather radar from the Koltsovo airport are used). Empirical dependences between precipitation intensity for short (30 minutes) time periods and reflectivity of clouds in the first surface layer (to the altitude of 1000 km) are derived for several weather stations. The stability of parameters of these dependences is assessed as moving away from the radar. Based on these dependences, we determined the areas of territory irrigation by precipitation of various intensity and the parameters of the areal rainfall reduction. Taking into account the previous studies, the “double-reduction” dependence of rainfall intensity on its time and irrigated area is developed. Preliminary calculations of precipitation intensity depending on time and irrigated area are performed for Yekaterinburg weather station.

The article provides an analysis of the spatiotemporal patterns in the dynamics of the main meteorological elements (air temperature and precipitation) in Crimea. Considering the significant geomorphological diversity and the peculiarities of the physiographical location of the Crimean Peninsula, ambiguous trends in the variability of climatic parameters are noted on its territory. Thus, the increase in air temperature and humidity has been recorded in the steppe and foothill areas during the recent decades. In contrast, at the Southern coast of Crimea, under the sub-Mediterranean climate conditions precipitation decreases and average annual air temperature stabilizes to the climatic norm. It is pointed out that the occurrence of spontaneous and dangerous hydrometeorological phenomena having frequented lately are due to the modern trends in the climate dynamics.