Intramonthly Variability of Daily Sea Level Pressure Anomalies in Russia Based on ERA5 Observations and Reanalysis Data

The variability of daily sea level pressure anomalies in Russia has been studied using weather stations data and ERA5 reanalysis for period 1970–2023. Four variability ranges: interdaily (<3 days) range, synoptic (4–9 days) range, the range of stable weather patterns (SWP, 10–30 days), and the intramonthly (<30 days) range have been analyzed. In the modern period (2000–2023), the most significant reduction (15–25%) in atmospheric pressure variability in interdaily and synoptic ranges was observed in winter in the southeast part of European Russia. On the contrary, a significant increase in variability has been observed for the range of SWP associated with episodes of prolonged atmospheric blocking in winter. In summer, pressure variability decreases in the synoptic range for the present period, with the exception of Western Siberia and southern regions of Russia. In the SWP range, a decrease in variability prevails in summer, with a maximal decrease of more than 15% in Eastern Siberia and an increase in variability in the Far East. Differences in the estimates of pressure variability from station data and reanalysis data have been analyzed. In winter and summer, in all ranges, reanalysis in Russia as a whole usually underestimates the variability of atmospheric pressure up to 5%. In winter in the regions of southern Siberia for the interdaily and synoptic ranges and in summer in the interdaily range on the ETR, there is a significant excess of variability by 5–10% according to reanalysis data. The revealed differences are statistically significant only in certain regions of Russia.