DETECTION OF DISCOMFORT INDEX WITH REMOTE SENSING TECHNOLOGY: THE CASE OF ANTALYA PROVINCE

Abstract. Thermal adaptation and thermal comfort indices are critical in determining the thermal comfort of the outdoor environment. They also play an essential role in research on heat stress, an environmental threat that can affect individuals' productivity, health and even survival. Urban growth and the resulting expansion of impervious surfaces affect the thermal characteristics of a landscape by raising Land Surface Temperatures (LST). The resulting warming can lead to thermal discomfort, the prevalence of heat-related health problems, air pollution, increased water use and energy demand for air conditioning, among others. Recently, efforts to understand the effects of urbanization and landscape changes on indoor and outdoor temperatures have increased significantly. Together with remote sensing technology, this study aims to understand human heat stress, and geographic information system (GIS) is a tool used in the research. In the estimation of heat stress, besides temperature, physiological status, environmental impact and relative humidity factors are also important. The discomfort index (DI) is a heat stress indicator proposed by Thom (1959), which expresses the contribution of air temperature and relative humidity to human thermal comfort. The discomfort index proposed by Thom (1959) was calculated as DI=0.5Ta+0.5Tw (Ta: dry bulb temperature, Tw: wet bulb temperature) modified by SOHAR, Adar and Laky (1963). In the study, the dry bulb temperature, assumed to be equal to the air temperature, was taken monthly from MODIS LST data at 1km resolution. Relative humidity was produced by interpolating 73 meteorological data in the study area at 1km resolution. Wet bulb temperature is difficult to measure, so it was calculated from dry bulb temperature and relative humidity data so that the discomfort index as a measure of heat stress in the study area was calculated with a resolution of 1 km. The discomfort index was calculated monthly and annually and classified according to Thom's 4 comfort classes. According to the calculation results, Antalya's average discomfort index value for the whole year is 24.9 °C, indicating that Antalya is a moderately comfortable place. This value varies monthly, especially in April and October when the heat stress is the highest.