%0 Journal Article
%T Validation of ASTER Surface Temperature Data with In Situ Measurements to Evaluate Heat Islands in Complex Urban Areas
%A Bonggeun Song
%A Kyunghun Park
%J Advances in Meteorology
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/620410
%X This study compared Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) surface temperature data with in situ measurements to validate the use of ASTER data for studying heat islands in urban settings with complex spatial characteristics. Eight sites in Changwon, Korea, were selected for analyses. Surface temperature data were extracted from the thermal infrared (TIR) band of ASTER on four dates during the summer and fall of 2012, and corresponding in situ measurements of temperature were also collected. Comparisons showed that ASTER derived temperatures were generally 4.27∼C lower than temperatures collected by in situ measurements during the daytime, except on cloudy days. However, ASTER temperatures were higher by 2.23每2.69∼C on two dates during the nighttime. Temperature differences between a city park and a paved area were insignificant. Differences between ASTER derived temperatures and onsite measurements are caused by a variety of factors including the application of emissivity values that do not consider the complex spatial characteristics of urban areas. Therefore, to improve the accuracy of surface temperatures extracted from infrared satellite imagery, we propose a revised model whereby temperature data is obtained from ASTER and emissivity values for various land covers are extracted based on in situ measurements. 1. Introduction Cities all over the world are experiencing more common urban heat islands (UHIs), whereby urban settlements are hotter than rural areas because of the rapid increase in artificial land cover such as asphalt [1每4]. Urban heat islands can generate tropical nighttime conditions and exacerbate heat waves, which negatively affects the health and welfare of urban residents [5每8]. Moreover, temperature increases from UHIs greatly increase energy consumption from the use of coolers [9, 10] and the aggregated effects from UHIs can cause changes in urban ecosystems [11]. The problems associated with UHIs are expected to worsen with global warming and UHIs are rapidly expanding into a global environmental issue of concern [12每14]. To alleviate adverse effects from UHIs, a wide range of studies have been performed using data on land surface temperatures (LSTs) extracted from remotely sensed thermal infrared data [15每18]. Surface temperature data derived from satellite images can be used to assess characteristics of UHIs such as how temperatures vary across the canopy layer of roofs and other surface features [19每23] or how temperatures are related to the surface energy balance [24每28]. In addition, satellite
%U http://www.hindawi.com/journals/amete/2014/620410/