Summer and Winter Anomalies in Day and Night Characteristics of Clouds Over Western Siberia Based on Modis Satellite Data and ERA5 Reanalysis Over the Period 2001–2022

The paper presents the results of an analysis of long-term variability of the characteristics of total cloudiness (night and day) over Western Siberia in the summer and winter seasons over the period 2001–2022 based on MODIS satellite data and ERA5 reanalysis. Three latitudinal zones of the target region are considered: northern (66°–72° N, 68°–82° E), transitional (60°–65° N, 62°–88° E), and southern (54°–59° N, 62°–88° E). Time series are constructed and, based on them, trends are determined for the following cloudiness parameters: the proportion of cloud cover over the study regions; the height, pressure, and temperature at its upper boundary; and the effective emissivity. It was found that, in 2010, 2012, 2014, and 2016, the greatest number of anomalies in the time series of the previously listed characteristics of daytime and nighttime clouds were observed. The results of a comparison of the considered cloud parameters with the variability of the temperature of the underlying surface and the heights of geopotentials at baric levels of 500, 700, 850, and 1000 hPa are presented. Hypotheses about the causes of the occurrence of anomalous values in the time series of the studied characteristics of daytime and nighttime clouds in the summer and winter seasons associated with the features of atmospheric circulations over Western Siberia in different years are discussed.