ИСТИНА

The main features of the urban heat island (UHI) in Moscow have been analyzed by data of weather stations including its annual course and long-term dynamics of the UHI. The maximal and average in space UHI intensities (comparison of air temperature T either in the city centre ΔTMAX, or in the urban area ΔTAV together with rural zone) are 1.9 and 0.9 ºC, respectively, in recent years. The UHI in Moscow has stabilized over past decade and is not growing due to deindustrialization and expansion of the city and also due to a drop in human activity during the COVID-19 lockdown in 2020. Under conditions of strong anticyclone in winter ΔTMAX reaches up to 11-12 ºC. In rare cases of dense Cb clouds, strong showers and thunderstorms above the city and clear sky at rural zone in summer both ΔTMAX and ΔTAV may be negative, so Moscow represents an inverse ‘urban cool island’. The UHI annual course is slightly pronounced. Usually it is stronger in summer and weaker in winter; however, in some months, the situation is reverse. The statistical significance of seasonal differences remains doubtful. Low cloudiness and amplitudes of diurnal air/surface temperatures demonstrate the closest relationship with the UHI intensity (with correlation coefficient R up to -0.67 for low cloudiness and ΔTMAX). The influence of wind speed V, total cloudiness and relative humidity on the UHI is weaker but still significant. The relationships of all meteorological parameters with ΔTMAX are closer than with ΔTAV. The multiple R between ΔTMAX and both parameters (low cloudiness and V) is ~0.8. For the first time for Moscow conditions, the UHI intensity functions of T, V and cloudiness were calculated and analyzed.