The spatial distribution of the annual mean urban heat island (UHI) intensity pattern was analysed for the medium-sized city Novi Sad, Serbia, located on the low and flat Great Hungarian Plain. The UHI pattern was determined by an empirical modelling method developed by (Balázs et al. 2009). This method was based on datasets from urban areas of Szeged and Debrecen (Hungary). The urban study area in Novi Sad (60 km2) was established as a grid network of 240 cells (0.5？km？×0.5？km). A Landsat satellite image (from June 2006) was used in order to evaluate normalized difference vegetation index and built-up ratio by cells. The pattern of the obtained UHI intensity values show concentric-like shapes when drawn as isotherms, mostly increase from the suburbs towards the inner urban areas. Results of this thermal pattern and determination of one of the local climate classification systems were used for recommending 10 locations for representative stations of an urban climate network in Novi Sad. 1. Introduction In the second part of the 20th century, urbanization accelerated and reached enormous magnitude. The growth rate of the Earth’s urban population is greater than that of the total population; therefore, more and more people live in urbanized regions. Nowadays, about half of the human population is affected by the burdens of urban environments: environmental pollution, noise, stress of the accelerated life-style, and last but not least the modified parameters of the urban atmosphere compared to the natural environment. This makes studies dealing with the urban impact on climate particularly important. Not only the large cities but also the smaller ones modify materials, structure, and energy balance of the surface and almost all properties of the urban atmospheric environment compared to the natural surroundings. Thus, owing to the artificial factors, a local climate (urban climate) develops which means a modification to the preurban situation. This climate is a result of the construction of buildings as well as by the emission of heat, moisture, and pollution related to human activities. According to Oke [1], two layers can be distinguished in the urban atmosphere. The first one is the urban canopy layer (UCL) containing air between the urban roughness elements (mainly buildings). It is a microscale concept, and its climate is dominated geographical factors and modified by the nature of the immediate surroundings. The upper boundary of the UCL is at about roof level. The second layer is the urban boundary layer (UBL) which is situated directly above the
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