Exploring the seasonality of surface urban heat islands using enhanced land surface temperature in a semi-arid city

Abstract

<p>Understanding the seasonal variations in surface urban heat island (SUHI) in different local climate zones (LCZs) is crucial to efforts to reduce the impacts of urban warming on local residents. However, such an understanding is constrained by the lack of land surface temperatures (LSTs) at both high spatial and temporal resolutions. This study created time series LSTs by fusing Landsat 8 satellite data and gap-filled MODIS products to further analyses of the SUHI seasonality in a semi-arid city, Xi'an, China. The results showed that LSTs of the open building types were generally lower than those of the compact building types. The highest SUHI intensity (7.17 degrees C) was found in 'compact mid-rise buildings' (LCZ2), whereas lowest (3.62 degrees C) was found in 'open high-rise buildings' (LCZ4) in July. The SUHI intensity peaked about 17-23 days later than the background LST. The annual SUHI hysteresis cycles exhibited an anti-clockwise concave-up pattern in the monsoon-influenced hot-summer humid continental climate (Dwa per Ko center dot ppenGeiger climate scheme). The SUHI intensity in autumn was higher than in spring under the same background LST. These results provide valuable information for developing heat mitigation strategies in different seasons.<br></p>