ИСТИНА

The urban ‘heat island’ in Moscow city has been investigated for the period since 1880s till nowadays using the data of the ground meteorological network. Besides a traditional intensity of the UHI (i.e. averaged in time difference between the air temperature in the city centre and outside the city) an additional parameter – so-called ‘areal’ UHI intensity – has been suggested. It represents a value averaged both in time and in space (a difference between mean air temperature in the city area and outside the city). As it is shown a mean usual intensity of the urban ‘heat island’ in Moscow was nearly of 1.0-1.2 ºC at the end of the 19th century, 1.2-1.4 ºC one century ago, 1.6-1.8 ºC both in the middle, and at the end of the 20th century and about 2.0 ºC at recent years. Correspondingly, the ‘areal intensity’ was equal to 0.8-0.9 ºC both in the middle, and at the end of the 20th century and nearly to 1.0 at recent years (in average from 2010 to 2014). Thus, during several decades both parameters remained nearly the same in spite of continued growth of the city, but at the nearest time new increase of them has been occurred. The probable explanation is that the urban growth in Moscow was extensive at the second part of the 20th century so that the urban saturation and density of heat sources in the centre of the city changed only a bit during that time. In the diurnal course the ‘heat island’ intensity in Moscow is maximal usually at night. The maximal ‘heat island’ intensity in Moscow may reach up to 14 ºC, usually at night or in the early morning. Weekly course of the air temperature in Moscow has been studied additionally because it is closely connected with the urban ‘heat island’ phenomenon. On the average during the last 50 years there was a gradual increase of T during week-days and sharp decrease (cooling) on weekends. This may be explained by industrial haze which is gradually accumulated from Monday to Friday and reduces effective nocturnal radiation in the city, especially during winter nights. Some general information about climate of Moscow and current tendency of its change will be given at the report as well.