ИСТИНА

Ground-based radiative measurements are the necessary tool for the accurate estimation of radiative regime in changing climate. In 2021, the Meteorological Observatory of Moscow State University acquired a set of KIPP & ZONEN instruments recommended for measurements at the Baseline Surface Radiation Network. They were used for the development of the RAD-MSU(BSRN) complex (Chubarova et al., 2022; Piskunova et al., 2024). The new complex provides high quality measurements of all components of the radiative budget, which allows us to characterize Moscow radiative climate in more detail, compared to the previous assessments. We present the analysis of Moscow radiative regime using RAD-MSU (BSRN) observations for the September, 2021 – December, 2023 period. We estimated the role of main geophysical factors, such as aerosol, surface albedo and cloudiness. We obtained, that in cloudless snow-free conditions, the losses in global shortwave irradiance (Q) are about 18–22% due to aerosol effect, which decreases direct irradiance and increases diffuse irradiance. In winter, the increase in Q in cloudless conditions is about 45 W/m2 (or 9%) at h = 30° due to reflection from the snow cover, smaller aerosol and water vapor content. At the same time, net shortwave irradiance (Bsh) demonstrates a significant decrease due to prevailing effects of snow albedo. In cloudy conditions, we obtained a nonlinear dependence of Q and Bsh cloud transmittance on relative sunshine duration, which can be a proxy of cloud parameter, for both winter and summer conditions. The study was supported by the Russian Science Foundation project № 23-77-01030. The work was performed within the framework of the MSU Collective Use Center (Monitoring of Atmospheric Radiation, № 460191494).