MESOSCALE CLIMATE OF THE MEGACITY OF MOSCOW

E. S. Grigorova

Analysis of the 30-year series of data from 30 stations in Moscow and the region shows that the effect of the megacity of Moscow manifests itself in increased air temperatures (“heat island”), increased precipitation, and increased frequency of adverse weather events. In summer, there are significant differences in air temperature between central Moscow and the suburbs. The differences range from —3 to 7ºC, with a modal value of 1.5ºC. Its frequency is close to 30%. The differences decrease by day (to 0.7ºC) and increase by night (to 2.5—3.3ºC). It is found that in summer there is a distinct zone of significant precipitation elongated from the center of the city to its northeast suburbs (with a maximum of 23 mm). The contribution of shower-type precipitation to daily mean precipitation in Moscow is at least 90%. Very heavy shower-type precipitation (≥ 50 mm/day) in the city center are observed at least once every 3—5 years, while in other districts of the city and in the region, once every 10—20 years. The maximum number of adverse weather events is shifted to the east (the downwind side) and is located at 25—30 km from the city boundary.