ИЗМЕНЧИВОСТЬ ЗИМНЕГО СТОКА РЕКИ ОКА В ЗАВИСИМОСТИ ОТ ИЗМЕНЕНИЯ КЛИМАТА

Response of a river flow in a winter low-water period to the climate changes is analyzed by the example of theOkaRiver(245 thousand km2). The analysis was done for each individual month from December to March during the period 1980–2015. The data were obtained for the hydrometric section Oka–Gorbatov. The following climatic characteristics were used for the analysis: 1) the number of days with positive air temperatures; 2) the temperature of the upper soil layer; 3) the sum of precipitation (data of meteorological station); 4) water equivalent of snow (the data from the satellite ESA GlobSnow, SWE version 2). Accuracy of the satellite data was estimated with respect to the observational data. In 1981–2010, significant increase in winter runoff occurred in December and March. This period was divided into two phases: 1) the end of the 20th century which was characterized by increasing of precipitation, the soil temperature, number of days with positive temperatures, and that resulted in the growth of the water equivalent of snow; 2) the beginning of the 21st century – by significant fluctuation in precipitation, number of days with positive temperatures as well as by a drop in the soil temperature and water equivalent of snow. The runoff volume was found to be in a direct relationship with the number of days with positive temperatures, the soil temperature, the precipitation sum, and in the inverse relationship with the water equivalent of snow. Both, the regression and dispersion analyses indicated that the above set of climatic characteristics was sufficient to explain changes in the winter runoff. According to the degree of influence on the winter runoff, these characteristics can be ranked as follows: the number of days with positive temperatures; the average soil temperature; the water equivalent of snow; the precipitation sum. The effect of the water equivalent on the runoff becomes significant from midwinter and remains the most significant factor by the end of snowmelt.Определена реакция зимнего стока рек в бассейне р. Ока (притока Волги) в 1981–2010 гг. на изменение климатических характеристик: суммы осадков, числа дней с положительными температурами воздуха и температуры верхнего слоя почвы, полученных по данным метеостанций, а также водного эквивалента снега, определённого по данным спутникового зондирования. Значимое увеличение зимнего стока в бассейне Оки наблюдается в периоды становления зимнего снежного покрова и начале снеготаяния

The influence of weather-climatic and social factors on population mortality from circulatory diseases in Russia

Aim. To study the links between the standard mortality rate of the population from circulatory system diseases (CSD) with factors: weather-climatic (inter-day jumps in air temperature and atmospheric pressure by seasons and for the year) and social (average annual income per person and the number of doctors of all specialties) in Russia for the period 1995-2015. Materials and methods. According to station data and data of reanalysis, seasonal and annual amounts of day-to-day jumps in air temperature were calculated more than the absolute value of 4° and 6°C and the atmospheric pressure more than the absolute value of 8 GPa. The links between climate variables and the mortality rate of the population, taking into account social factors, were investigated using factor analysis, including regression and variance analyses. Results. Annual amounts of temperature (pressure) jumps of different signs vary greatly on the territory: the maximum amounts are 3-4 times higher than the minimum ones. The geographical distribution of air temperature fluctuations differs from the distribution of atmospheric pressure fluctuations. The sum of temperature jumps in the absolute value of more than 6°C is about twice less than the sum of jumps more than 4°C, but they are characterized by similarity of geographical distribution. The sum of the jumps of temperature (pressure) is reduced during the summer is approximately two times compared to the winter. The maximum jumps are observed mainly in the Northern regions with low population density, but with high per capita income, while the minimum is observed in the South-Western parts of the European part of the country with high population density, as well as middle and low income. Global warming does not significantly affect the reduction of annual amounts of temperature (pressure) jumps. Factor analysis of social and climatic variables in the territory for each year indicates the dominance of the influence of the social factor (per capita income) on the mortality rate from CSD. Conclusion. Factor analysis is integrated in the annual scale climatic and social variables showed a dominant effect on the coefficient of mortality from CSD, the factor of standard of living (per capita income of the population). Then the significance of the impact factors is consistently reduced: negative atmospheric pressure jumps, average seasonal pressure, health care level, positive pressure jumps. The significance of temperature variables is the smallest

Cроки залегания снежного покрова на территории России в начале ХХI в. по спутниковым данным

Time of the snow cover appearance, existence and disappearance on the Russia’s territory in the early 21st century (2000–2015) was corrected using the MODIS/Terra satellite data (the 8-day discreteness, and the 0.5×0.5° resolution). The satellite data errors were estimated from data of the ground stations observations. The errors were found to be maximal in autumn and minimal in spring. The relationship between the snow cover characteristics and the climate ones was investigated using data obtained at the ground-based stations together with correlation between dates of snow appearance and loss and the climate parameters. The dependences obtained were tested by means of correlation and regression analysis over the longitudinal sectors. Significant coefficients of correlation (the Student criterion of probability was equal to 0.95) were found between time of the snow cover presence and dates of the temperature drop below 0 °С and the amount of days with negative temperatures. Changes in the climate characteristics result in that due to decreasing of the solid precipitation in winter time the snow presence duration becomes shorter over the European part of Russia and in the Western Siberia. The shortening in the Middle Siberia is caused by the spring warming. Durations of the snow occurrence in the Far East area are different. On the Chukotka peninsula the duration is longer because of the autumn fall in temperature while in the Kamchatka region the snow occurrence time is shorter due to significant decrease of a period with negative temperatures in both the autumn and spring seasons.Оценена погрешность определения параметров снежного покрова в осенний и весенний периоды по спутниковым данным MODIS путём сравнения с материалами наземных наблюдений. По данным MODIS уточнены сроки установления и схода снежного покрова, а также продолжительность его залегания в 2000–2015 гг.; приведены карты этих характеристик. Отслежены тренды характеристик залегания снежного покрова на территории России в разных долготных секторах

Изменения климата и снежного покрова с точки зрения функционирования горнолыжных курортов России в начале xxi века

The development of winter ski tourism and characteristics of ski resorts in various regions of Russia are closely related to climatic conditions, the most important of which are the presence and duration of snow cover. For the period 2000–2021, a study of snow cover, availability of “optimal ski days” and climatic indicators necessary for artificial snowmaking at ski resorts located in different regions of Russia was performed, using data of the reanalysis ERA5-Land. The characteristics of snow cover and temperature from the reanalysis data were compared with data of the meteorological network. The ERA5-Land data for temperature, precipitation, and snow cover thickness are well synchronized with the observational data, and estimates of the error of trends in air temperature and snow cover depth according to the reanalysis data relative to the station data give satisfactory results. In the conditions of the current climate, the average and maximum thickness of snow cover in all resorts is sufficient for their functioning, but in 2000–2021, a decrease in both the maximum and average values of snow cover is noted in most resorts. The study shows that in terms of snow and weather conditions, the highest mountain resorts of the North Caucasus and Kirovsk (Murmansk region) are the most prosperous, where thickness of the snow cover and duration of its occurrence as well as a significant number of “optimal ski days” sustains stability of the resorts and creates favorable conditions for their further development.Проведено исследование характеристик снежного покрова на горнолыжных курортах по данным реанализа ERA5-Land. Выполнено сравнение характеристик снежного покрова, осадков и температуры по данным реанализа и метеосети. В условиях современного климата средняя и максимальная высота снежного покрова на всех курортах достаточна для их функционирования, но на большинстве курортов наблюдается уменьшение высоты снежного покрова

Использование реанализа ERA5–Land и данных метеостанций в горных районах России для оценки изменения ледниковых систем Восточной Сибири и Дальнего Востока

This work involving the study of changes in the glacier equilibrium line altitude (ELA) is a continuance of the glaciological parameters of mountain systems investigation. The article explores the possibility of using new generation climate archives (in this case, ERA5–Land) together with weather station data on temperature and precipitation, in order to assess the climate dependence of the glacial system ELA in hard-to-reach and insufficiently studied mountain regions of the Russia Asian part. The ERA5–Land reanalysis reproduces temperature (values, dynamics, and trends) quite well in mountain systems. The use of total precipitation is possible only for assessing their dynamics and trends. The relative error for temperature trend is below 20% in both positive and negative sides, and precipitation is less than 30% in the negative one. Positive temperature trends of different intensity are observed in all mountains of the Russia Asian part with a maximum in the mountain systems of the Arctic zone. Minimal temperature trends are distinctive for coastal mountain regions of temperate latitudes. Summer temperature trends are maximum in inland areas and minimum in coastal mountain areas. The increase in precipitation in such areas occurs mainly at the expense of the cold period. It was revealed there was an increase of the glacial systems ELA from 50 to 800 m in the mountain regions of the Asian North Russia within 1966–2021. The value of the ELA rise coincides with areas of high temperature trends and may not correspond to precipitation negative trends.Исследуется возможность совместного использования реанализа ERA5–Land и станционных данных для оценки высоты границы питания ледниковых систем. ERA5–Land хорошо воспроизводит температуру и удовлетворительно тренды осадков. Положительные температурные тренды разной интенсивности наблюдаются во всех горных районах. Наблюдаемое увеличение высоты границы питания ледников совпадает с областями высоких температурных трендов

Определение снегозапасов Западной Сибири по расчётам на модели локального тепловлагообмена SPONSOR с использованием данных реанализа

Obtaining of reliable information about the characteristics of snow cover with high spatial and temporal resolution for large areas of Northern Eurasia, with rare or absent network of ground-based observations stations is an important and urgent task. Currently estimation of the value of the snow water equivalent (SWE) and the snow depth have a large degree of uncertainty, especially if we are moving from data at the point of observation stations to distributed space values. In this article, the simulations of SWE and the snow depth using Land-Surface Model (LSM) SPONSOR with input meteorological data taken from the ECMWF ERAInterim reanalysis was performed for Western Siberia for the period from 1979 to 2013. Fields of SWE and of the snow depth with high spatial and temporal resolution corresponding to the resolution of meteorological data of the ECMWF ERA-Interim reanalysis (time step of 6 hours, the grid resolution of 0.75° × 0.75° in latitude and longitude) were obtained. For the entire period SWE data were compared with observations, as simulated using the model and taken directly from the reanalysis ERA-Interim at points corresponding of observation stations. Also comparison of observations and satellite data of SWE for points of observation stations was performed. Correlation coefficients between observations and model and satellite data for SWE and the snow depth were calculated for the period from 1979 to 2013. These correlation coefficients between observations and results of simulations using LSM SPONSOR for SWE, and especially for the snow depth are the best of all methods. Maps with high spatial resolution for SWE, obtained by different methods, were constructed for February averaged. Comparing of constructed maps shows significant uncertainty of the SWE fields, besides field’s distortions are not evenly distributed across the region. It appears that no one of these methods currently can be used as a reference (unique) to determine SWE in the absence of data of ground-based observations. Overall, model simulations using LSM SPONSOR somewhat overstate SWE, however, this overestimation is not more than 10–20% for most part of the territory, except in the South. Model data are reasonably well reproduce SWE for Central, Eastern and, most probably, for Northern parts of the region, differing from a real at 10–15%. Data from used satellite archive a few underestimate of SWE. SWE data taken directly from the reanalysis ERA-Interim, give large distortions of the SWE field: these values for Northern parts of the region, are likely greatly underestimated, and for Western and Eastern parts of the region – inflated. It is shown that in general, the method of simulation of snow cover characteristics using LSM SPONSOR with input data taken from the ECMWF ERA-Interim reanalysis gives good results for the region of Western Siberia.Для территории Западной Сибири за период с 1979 по 2013 г. проведены расчёты снегозапасов и толщины снежного покрова с помощью модели локального тепловлагообмена SPONSOR с входными метеоданными, взятыми из реанализа ECMWF ERA-Interim. Показано, что коэффициенты корреляции между данными наблюдений и результатами численных расчётов на модели SPONSOR – наилучшие из всех методов. С помощью модели SPONSOR достаточно хорошо воспроизводятся данные снегозапасов по центральной, восточной и, наиболее вероятно, северной частям Западной Сибири

Влияние притока тёплых атлантических вод на аномалии климата в атлантическом секторе Арктики

Significant climatic changes of oceanic and atmospheric elements and a relation of them to the ocean surface winter anomalies in North Atlantic are analyzed in the paper. Periods of «warm» ocean (2002–2012) and «cold» ocean (1960–1970) were determined. Positive anomalies of the ocean surface temperature increase the ice-free water area and, correspondingly, decrease the ice-field area. As a result of such changes in a state of the ocean surface (open water and ice), surface air temperature rises, and, consequently, atmospheric pressure in central part of a given Arctic sector drops.Исследованы значимые климатические изменения океанических и атмосферных переменных в атлантическом секторе Арктике, определяемые аномалиями температуры поверхности океана зимой. Определены периоды «тёплого» (2002–2012 гг.) и «холодного» (1960–70‑е годы) океана.Положительная аномалия температуры поверхности океана вызывает увеличение площади свободной ото льда воды и сокращение площади сплошных льдов. В результате такого изменения свойств подстилающей поверхности (открытая вода и лёд) растёт приземная температура воздуха и, как следствие, понижается давление в центральной области заданного сектора Арктики

Положения арктического фронта в периоды похолодания и потепления Арктики

Winter positions of the Arctic front (AF) during the known periods of the climate cooling (1949–1980) and warming (1981–2012) were analyzed within the sector 10° W – 60° E. The AF positios were determined by the following indicators: 1) a surface pressure; 2) horizontal wind divergence; 3) geostrophic vortex; 4) geostrophic heat advection. The main extrema of these four dynamic characteristics coincide and fall on the latitude 72.5° N. This corresponds to the average position of the AF for a given resolution and confirms correctness of our choice of these characteristics as the AF indicators. Relative differences between mean profiles of all values of the above warm and cold periods were calculated using method of normalization of each value for the corresponding latitude by the standard deviation for the entire period (1949–2012). To study variability of the AF position we used mean yearly winter profiles of the variables under investigation together with the statistical analysis of positions of the extrema within the latitude degrees. For pressure and geostrophic advection positions of the absolute minima were determined while for geostrophic vortex and divergence – positions of the absolute maxima. The data show that according to different criteria the AF average positions for the period 1949–2012 lie within the zone 72.4–73.4 N. The interannual variability of the AF positions lies within the 1–2 degrees of latitude and corresponds to the range of the air temperature variability above the zone of maximal changes in the sea ice area. According to the standard deviation values of the divergence and the geostrophic vortex are the most stable in region of the AF passage. Comparison of differences of the studied characteristics between the warm and cold periods shows that the changes in the AF positions are not statistically significant (P(t) < 91% t‑criterion) unlike the changes in positions of isolines which characterize the warming (P(t) = 100%). Thus, despite significant changes in properties of the surface and the temperature regime to the north of 72.5 N (the warming), according to all the criteria the AF climatic position remains quasi‑stationary for 32‑year periods of averaging.Исследовано зимнее положение арктического фронта в секторе 10° з.д. – 60° в.д. в периоды похолодания (1949–1980 гг.) и потепления (1981–2012 гг.) Арктики. Положение арктического фронта определялось по положению минимума давления и геострофической адвекции, максимумам геострофического вихря и дивергенции ветра. Установлено, что разности в положении арктического фронта для периода потепления и похолодания статистически незначимы для всех перечисленных параметров и положение арктического фронта можно считать квазистационарным при значительном потеплении на 3–6 °С за 32 года

Региональные особенности изменения зимних экстремальных температур и осадков на территории России в 1970–2015 гг.

Te space-time dynamics of the occurrence of winter extreme events is investigated on the territory of Russia in 1970-2015 on the basis of daily observations at weather stations. It was found that a whole on the territory a noticeable increase in the occurrence of days with extremely high daily temperatures and daily precipitation and a decrease in the occurrence of extremely cold days was noted. Te most noticeable changes happened in the European part of Russia, where at the beginning of the XXI century occurrence of the extremes was greater than during the previous thirty years. Note also that at the beginning of XXI century in Southern Siberia increase of occurrences of both daily maximum and daily minimum temperature was concurrent. Tis combination appears to be caused by the increase in temperature variability in the region due to the alternation of winters with extreme frosts and warmer and wet winters. Te increase in the frequency of extremely high temperatures in the European part of Russia could have been caused by both general warming and the increased influence of AMO. An increase in the frequency of extreme high and low temperatures in the south of Siberia may be due to the formation of an anticyclonic circulation anomaly with a center near the coast of the Kara Sea, which is responsible for advection of cold air masses from the northeast. As well as cyclonic formation in southern Siberia, along the eastern periphery of which temperate latitudes can receive anomalously warm air from the subtropics.Исследована повторяемость экстремальных явлений зимой на территории России в 1970–2015 гг. на основе суточных данных наблюдений на метеостанциях. Отмечен рост повторяемости дней с высокими суточными температурами, суточными суммами осадков и уменьшение морозных дней. Самые большие изменения наблюдаются в Европейской части России. На юге Сибири в начале XXI в. одновременно увеличилась повторяемость морозных и тёплых дней, а также дней с экстремальными зимними осадками

Климатические вариации арктического фронта и ледовитости Баренцева моря зимой

Climatologic Arctic front location at Atlantic-European section and changes in Barents sea ice coverage during periods of Arctic warming (1981–2010) and cooling (1948–1980) are studied 7by reanalysis data (UEA CRU and NCEP/NCAR). As we demonstrate, Arctic front structure is more complex than was considered before. Arctic front consists of two branches, main one over Atlantic ocean, Norwegian and Barents seas and secondary one over Northern Europe. Main front divides arctic and temperate air masses over Atlantics as well as arctic and subarctic (transformed temperate masses over Northern Europe) masses over Arctic seas. Secondary (subarctic) branch separates subarctic air masses from continental temperate masses. Main and secondary Arctic front branches remain quasi-stationary during observed periods. On climatic scale, Arctic front is conservative with respect to cyclonic activity change during periods of warming and cooling in Arctic. Cyclonic activity, which is determined by cyclone centres repeatability, increased synchronously in Arctic and Subarctic from cooling period (1948–1980) to actual warming. Evidences to meet hypothesis on positive feedback between warm Atlantic water masses inflow and Barents sea wintertime ice coverage. This hypothesis became particularly important in relation with model reproduction of turbulent warm heavy stream that cause convection and cyclonic turbulence in lower troposphere. In feedback forming, cyclone centres localization matters; their repeatability is calculated for climatic episodes 1991–2007 (small ice coverage) and 1979–1990 (big ice coverage) in Barents sea’s four sections. During climatic episode 1991–2007 cyclone centres repeatability increased mostly in western sections, while in eastern sections repeatability decreased. At the same time, cyclone localization increase mostly in north-west section, comparing with south-western one. Cyclone centres localization shift north cause ice coverage decrease there.По данным реанализа (UEA CRU и NCEP/NCAR) исследованы размещение климатического арктического фронта в Атлантико-Европейском секторе и изменение ледовитости Баренцева моря зимой в периоды современного потепления (1981–2010 гг.) и похолодания (1948–1980 гг.) Арктики. Установлено, что арктический фронт имеет двойственную структуру и состоит из основного (над морями Северной Атлантики) и вторичного (в северной части континента). В рассмотренные периоды похолодания и потепления Арктики размещение основной и вторичной ветвей этого фронта квазистационарно. Рост локализации центров циклонов в западных секторах Баренцева моря в 1991–2007 гг. подтверждает модельные оценки увеличения возникновения циклонических возмущений в атмосфере над свободной ото льда поверхностью Баренцева моря, что вызывает положительную обратную связь и способствует уменьшению площади ледяного покрова