The light climate of Moscow is presented based on the long-term observations of natural illuminance of the Earth’s surface, illuminance of differently oriented vertical surfaces, and factors influencing their variability, which have been performed at the Moscow State University Meteorological Observatory. The obtained normals are sufficient for any practical applications in most cases. An issue analyzed in the study is conditions that lead to a decrease in illumination below the critical values for which the use of combined or artificial lighting of premises is required. It is shown that illumination can be forecasted based on low-level clouds predicted using a general weather forecast.

Based on long-term (1955–2018) actinometric observations at the Meteorological Observatory of Lomonosov Moscow State University, the radiation regime of the Earth’s surface is analyzed. The assessment of factors determining the arrival and redistribution of solar and terrestrial radiation is given. A climatic generalization of radiation characteristics is presented: their climate normals, the limits of daily, annual, and long-term variability are determined. The climatology of atmospheric counterradiation (1966–2018) is provided for the first time. Trends in atmospheric radiation parameters indicating current climate change are analyzed. Some aspects of the radiation climate are considered taking into account the requirements of consumers of actinometric information. The presented information can be used by a wide range of specialists for solving scientific and practical problems.

The detailed analysis of variations in sunshine characteristics in Moscow in 1955–2017 is provided using observational data from the Moscow State University Meteorological Observatory. The regression equations between sunshine duration and radiation characteristics are derived. The possibility of their application to different geographic regions is assessed.

The possibility is considered ofusing calculated and satellite data in addition to the results of direct actinometric observations in order to maintain the series of Earth surface radiation budget and to study its spatial variability. The empirical relationships are obtained based on the regression analysis of atmospheric radiation and meteorological parameters using the data of long-term observations in Lomonosov Moscow State University Meteorological Observatory (MSU MO). Satellite data needed to compute the Earth surface radiation budget are compared with the respective data of ground-based observations in MSU MO, and the possibility of using them is assessed.

The work is devoted to assessment of solar energy resources for the territory of Moscow. The authors consider the various sources of input data on the incoming solar radiation - the long-term ground-based measurements and spe cialized data bases (NASA POWER). Verification of the NASA POWER data on the base of observations of weather stations in the Moscow region should justify its use under the calculation of resources and performance prediction of solar power plants. The work shows and discusses the results of calculations of solar energy potential on this territory.

We have estimated and compensated the error in long-term series of the aerosol optical thickness (AOT) calculated from the data on direct integral solar radiation measured by a standard actinometer at the Meteorological Observatory of the Moscow State University (MO MSU) for strong atmospheric turbidity conditions. The necessary corrections have been obtained by the Monte-Carlo simulation of the actinometry measurements for different atmospheric conditions, taking into account the angular size of the field of view of the instrument; and a special correctional formula has been obtained. This correction formula has been applied for all timed AOT values of above 0.5 observed at the MO MSU for the entire time period from 1955 to 2013. Changes in the long-term average AOT values in Moscow occurred only when the smoky haze from the forest and peat fires affected the aerosol turbidity of the atmosphere. Here, the significant decreasing trend of aerosol optical depth of the atmosphere from 1955 to 2013 has been retained with the same confidence level.

Variations in radiation fluxes and the factors that define them and their redistribution in the atmosphere are analyzed using the data of long-term ground-based measurements at the Meteorological Observatory of Lomonosov Moscow State University. It is demonstrated that since the middle of the 1990s trends in many atmospheric radiation parameters have changed as compared to the trends observed in the previous years. For some parameters the trends are significant, are kept for a long period of time, and. hence, can be considered as climate changes. The potential effects of these changes on the regional warming are assessed.

Analyzed are the results of meteorological and environmental measurements performed over the 60-year period (1954–2013) at the Meteorological Observatory of Lomonosov Moscow State University. The significant positive temperature trend (0.04°C/year for 1954–2013) was obtained; it increased up to 0.07°C/year in 1976–2012. Considered are the features of seasonal variations of different atmospheric characteristics. Discussed are the type and causes of low-frequency changes in meteorological parameters, radiation balance components, radiation in different spectral ranges, and chemical composition of precipitation. Demonstrated are possible mechanisms of the more significant increase observed in air temperature in Moscow as compared with that in Central Federal District and their connection with the greenhouse effect in the urban atmosphere.

Анализируются результаты измерений метеорологических и экологических величин за 60 лет (1954-2013 гг.), выполненных в Метеорологической обсерватории МГУ им. М. В. Ломоносова. Получен значимый положительный тренд температуры (0,04°С/год за период 1954-2013 гг.), который в 1976-2012 гг. увеличился до 0,07°С/год. Рассматриваются особенности сезонного хода разных характеристик атмосферы. Обсуждаются характер и причины низкочастотных колебаний метеорологических величин, составляющих радиационного баланса, радиации в разных спектральных диапазонах, а также химического состава атмосферных осадков. Показаны возможные механизмы наблюдаемого более значительного увеличения температуры воздуха в Москве по сравнению с Центральным федеральным округом и их связь с парниковым эффектом в городской атмосфере.

Presented are the results of the analysis of the series of seasonal and annual means of short-wave solar radiation measured at 180 actinometric stations of Europe in 1964–2010. It is demonstrated that there are two strongly pronounced periods, namely, the decrease from the early 1960s to the late 1980s and the increase in the subsequent 20 years. Total solar radiation decreased by 1.8% per 10 years on average during the first period and increased by 2.9% per 10 years during the second period. The increase in solar radiation during the second period is observed at the majority of stations due to the increase in the direct solar radiation (by 8.3% per 10 years on average). The diffuse radiation decreased by 3.1% on average for that period. The highest values of the ratio of the diffuse radiation to the direct one were registered in the 1980s–early 1990s.