Long-term (up to 165 years) series of globally averaged values of the main water exchange components, obtained as the result of historic experiments on several dozen (from 34 to 41) climate models of CMIP-6 project, are analyzed. The examined characteristics include variations of evaporation from ocean surface, precipitation over the ocean, effective evaporation from the ocean (total horizontal moisture transfer in the atmosphere from the ocean to land), and total model river runoff from the continents. It is shown that the model precipitation over the ocean effectively filters out the monotonic positive trend in evaporation from the ocean and, therefore, increases the stationarity of the total chain of global water exchange, including long-term changes in the global river runoff.

Archives of data on the most important reservoirs and flowing lakes of the world, and on long-term changes in the flow of rivers regulated by them have been formed. The features of the parameters of artificially regulated rivers and lacustrine rivers and the dependence of these parameters on the characteristics of reservoirs and lakes were analysed. A phenomenon of «monotonous» and «intermittent» nonstationarity are described. The possible role of reservoirs and lakes in their formation has been assessed.

A joint data repository on flowage lakes of the world and long-term flow variations in the rivers they regulate has been formed. The specific features of the flowage lake parameters have been analyzed along with their dependence on the characteristics of the lakes. A hypothesis has been proposed implying the global invariance of the coefficient of water exchange of lakes with respect to the average volume of flow through the lakes. The effect of the coefficient of lake water exchange on the long-term flow variations of the rivers regulated by the lakes has been studied. It has been shown that an increase in this coefficient is accompanied by a decrease, on the average, of the correlation between the annual, maximal, and minimal flow of successive years, as well as the average orders of the autoregression models describing the long-term variations of all types of flow. The effect of intermittent nonstationarity has been described for the series of annual runoff values for some lake-containing rivers.

Data on 388 world reservoirs and changes in the annual, maximal, and minimal runoff in the rivers they regulate at the same number of gages have been generalized over 102 items for each series. The existence of reservoirs has been shown to cause, on the average, an increase in the coefficients of variation and asymmetry for long-term variations of river runoff along with an increase in the correlation between the annual (this is not true for the annual runoff of the rivers that are regulated by HPP reservoirs), maximal, and mi-nimal runoff of successive years, the orders of autoregression runoff models, and the share of runoff series that are nonstationary in terms of expectation. The effect of the regulating capacity of reservoirs ("regulation degree") on the characteristics of long-term runoff variations has been analyzed. The subtler structure of long-term runoff variations of regulated rivers have been studied to identify the effect of "intermittent nonstationarity"-a runoff series of a regulated river can contain alternating segments corresponding to fragments of realizations of random processes with statistically significant positive and negative trends or with no trends. It is hypothesized that the construction of reservoirs causes a spontaneous increase in the intermittent nonstationarity in the variations of river water abundance.

Н.А. Дианский1,2,3), И.В. Соломонова4), А.В. Гусев2,5) 1) Московский государственный университет им. М.В. Ломоносова, Москва 2) Институт вычислительной математики им. Г.И. Марчука РАН, Москва 3) Государственный океанографический институт им. Н.Н. Зубова, Москва 4) Институт водных проблем РАН, Москва 5) Институт океанологии им. П.П. Ширшова РАН, Москва nikolay.diansky@gmail.com, _iren@mail.ru, anatoly.v.gusev@gmail.com

Based on the analysis of 162 longest (more than 100 years each) series of annual, maximal, and minimal runoff in rivers of different genetic types, the regularities of changes in the degree of stationarity/nonstationarity of the runoff changes are studied. It is shown that changes in the average annual and maximum runoff in the rivers of the “main” type—non-effluent, unregulated, as well as in the rivers of glacial feeding—throughout the period of observations generally correspond to the stationarity hypothesis. On the contrary, for a significant part of the runoff series of all types of effluents and regulated rivers, as well as the minimum flow of rivers of the main type, the alternation of segments of realizations of stationary and nonstationary processes with respect to mathematical expectation, is typical. To describe this effect, we propose the concept of “intermittent” nonstationarity. The nonstationarity parameters of the indicated type are compared with the nonstationarity parameters of the monotonous type.

ОЦЕНКА КЛИМАТИЧЕСКИХ ИЗМЕНЕНИЙ В АРКТИКЕ В ХХI СТОЛЕТИИ НА ОСНОВЕ КОМБИНИРОВАННОГО ПРОГНОСТИЧЕСКОГО СЦЕНАРИЯ Г. Н. Панин Институт водных проблем РАН (Москва, Российская Федерация) Н. А. Дианский Московский государственный университет им.М. В. Ломоносова, Институт вычислительной математики РАН, Государственный океанографический институт им.Н. Н. Зубова (Москва, Российская Федерация) И. В. Соломонова Институт водных проблем РАН (Москва, Российская Федерация) А. В. Гусев Институт вычислительной математики РАН, Институт океанологии им.П. П. Ширшова РАН (Москва, Российская Федерация) Т. Ю. Выручалкина Институт водных проблем РАН (Москва, Российская Федерация

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.

Причина колебания уровня Каспийского моря, прогноз его изменений по-прежнему остается одной из нерешенных задач. В данной работе предлагается новый подход, базирующийся на результатах анализа воздействия Северной Атлантики на формирование климата бассейна Каспийского моря. Приведены результаты анализа транспорта влаги в бассейн Каспийского моря, а также связи осадков и температуры в бассейне Каспийского моря с индексами атмосферной и океанической циркуляции, приходившиеся на период спада и подъема уровня Каспия. Исследования транспорта влаги с Северной Атлантики, выполненные впервые, показали, что он является определяющим в формировании уровенного режима Каспийского моря.

The cause of Caspian level variations is still to be found, and their forecasting is still among the problems to be solved. This study proposes a new approach based on the results of analysis of the effect the North Atlantic has on climate formation in the Caspian Sea basin. The article presents the results of analysis of moisture transport into the Caspian Sea basin, as well as a relationship between precipitation and temperature in this basin and the indices of atmospheric and oceanic circulation for the periods of Caspian level drop and rise. A pioneer study of moisture transport from the North Atlantic showed this transport to govern the formation of Caspian Sea level regime.

Обобщены результаты исследований гидрологического режима Каспийского моря и климата его бассейна за период наблюдений 1945–2010 гг. Приведены результаты анализа режима атмосферных осадков, температур воздуха бассейна Каспийского моря и его уровня, а также стока р. Волги, приходившиеся на период спада и подъема уровня Каспия. Показана согласованность в изменении тенденций уровня Каспийского моря и климата его бассейна, обосновано направление дальнейших исследований.

The results of studying the hydrological regime of the Caspian Sea and its basin climate in observation period 1945–2010 are generalized. The results of analysis of the regime of precipitation, air temperature in the Caspian Sea basin and its level, as well as Volga runoff in periods of Caspian Sea level rise and drop are given. The conformity in variations of the trends in Caspian Sea level its basin climate is demonstrated, and the direction of further studies is substantiated.

An algorithm is proposed for simulating a hydrological random process for the case of a vector, whose components are runoff values for the Khoper R. in three high-water months and the Volga R. in February, April, and the average over April, May, and June. The simulation is shown to have a high accuracy: the expectations and the coefficients of variation exactly coincide with specified values; the skewness has an accuracy of 0.1; the deviation of the coefficients of autocorrelation and cross-correlation of vector components from the specified values never exceeds 0.05.

Air temperature variations are studied in the territory of the middle and high latitudes of the Northern Hemisphere. Estimates of the intraregional homogeneity of current climate changes were used to carry out zoning by several criteria for the XX and early XXI centuries. Six zones with typical climate change were identified: the Pacific, Canadian, Atlantic, European, Siberian, and Far Eastern. A new approach is proposed to the description of possible regional and global climate changes in the Northern Hemisphere basing on a combination of “greenhouse” and “rotational” effects. It is shown that the data on variations in the angular velocity of the Earth’s rotation can be used as a universal indicator of climate changes on the planet. The proposed approach made it possible to account for not only the growth in temperature caused by greenhouse gas emission, but also climate changes (in particular, the cooling of the 1940s–1970s). A concept is developed, allowing a new scenario of possible climate changes in the XXI century to be proposed.