The impact of urban areas on various meteorological variables: The “urban meteorology island”

The urban heat island (UHI) is well-known phenomenon, however, also other meteorological field are significantly affected by urban environment. The WRF and RegCM regional climate models with various setting were used to determine overall weather and climate alteration due to urban surfaces. Simulations were run on 9 km domain covering the center of Europe and time area of years 2015 and 2016. Validation of results was performed by E-OBS, ECAD and MODIS data. The urban effects were studied for 10 chosen big cities across domain, nearly all studied variables manifest statistically significant differences in urban areas. Cloud cover is increased in cities mainly in summer afternoons, together with sub-grid-scale precipitation. Specific humidity is decreased during day-time in summer and also in winter. In view of differences between models, the urban effects are more pronounced in WRF than in RegCM model. Finally, as a generalization of UHI and similar phenomena defined already, we can define urban meteorology island (UMI) as a single phenomenon covering all specific features as UHI as components of UMI.