Atmospheric urban heat island detection by direct measurements in Cluj-Napoca city, Romania
The intensification of the urbanization process in the last decades affects not only the quality of the environment but also the quality of life in large cities worldwide. In Romania, as a former communist country, another important process that has a major influence for the urban climate is the forced industrialization from the communist era. One of the most important consequences of the above mentioned processes is the urban heat island (UHI), a climatic phenomenon that involves increased air and surface temperature values in the city when compared to the nearby rural areas.
The purpose of this study is to identify these temperature differences and to obtain the first overview of the atmospheric urban heat island (AUHI) in Cluj-Napoca city, Romania. In order to highlight the intensity of this phenomenon in the study area, a mixed method has been used that combines a mobile transverse study on three different routes along the city street network, performed by car, with observations in fixed, representative points from the city. All the observations have been performed at 1.5 m above the ground level, during the night, in different seasons and weather conditions. The data that resulted from the mobile transverse method have been subjected to time and altitude corrections, based on the fixed points measurements. The deviation of all the points compared to the center of the city has been computed. The hot spots of the cities have been identified in central area and in concrete block of flats neighborhood. The results of the research are detailed in the content of the paper.