Quantitative-spatial relationships between air and surface temperature, a proxy for microclimate studies in fine-scale intra-urban areas?

Recent studies on fine-scale spatial variations of urban air temperature revealed that urban environments are urban heat "archipelagos", rather than "islands,” and there are locations with higher temperatures which suffer more intensive urban heat, and people in these areas are likely to experience greater heat stress and health risks. However, study of this phenomenon is limited because of insufficient air temperature data at the fine scale. This study attempted to quantify the heterogeneity of air and land surface temperature (LST), and their relationship in a fine-scale urban environment using field-measured air temperature and Landsat 8-based LST data. We found: (1) there was a strong thermal heterogeneity at the fine scale even between the measurement points on the edges of a large urban park. The maximum temperature difference reached 4.2 °C for air temperature and 8 °C for LST in the study area. (2) Air and surface temperatures were positively correlated. However, their cool and hot spots did not always overlap in space. (3) air temperature is more complex than LST, and more parameters in the urban environment can influence air temperature. (4) Urban landscape and climatological parameters can enhance the applicability of LST as a proxy for air temperature from 39% to 57%. The results have theoretical and practical implications for identifying the locations on a fine scale with extreme heat and attracting the attention of urban planners to take adoption measures.