Chen Feng, Yang Song, Yin Kai, Chan Paul
School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai 519082, China; Institute of Earth Climate and Environment System, Sun Yat-sen University, Guangzhou 510275, China; Fujian Key Laboratory of Sensing and Computing for Smart City, Xiamen University, Xiamen 361005, China.
School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai 519082, China; Institute of Earth Climate and Environment System, Sun Yat-sen University, Guangzhou 510275, China.
J Environ Sci (China). 2017 Sep;59:80-88. doi: 10.1016/j.jes.2017.02.009. Epub 2017 Feb 24.
Since the launch of its first satellite in 1972, the Landsat program has operated continuously for more than forty years. A large data archive collected by the Landsat program significantly benefits both the academic community and society. Thermal imagery from Landsat sensors, provided with relatively high spatial resolution, is suitable for monitoring urban thermal environment. Growing use of Landsat data in monitoring urban thermal environment is demonstrated by increasing publications on this subject, especially over the last decade. Urban thermal environment is usually delineated by land surface temperature (LST). However, the quantitative and accurate estimation of LST from Landsat data is still a challenge, especially for urban areas. This paper will discuss the main challenges for urban LST retrieval, including urban surface emissivity, atmospheric correction, radiometric calibration, and validation. In addition, we will discuss general challenges confronting the continuity of quantitative applications of Landsat observations. These challenges arise mainly from the scan line corrector failure of the Landsat 7 ETM+ and channel differences among sensors. Based on these investigations, the concerns are to: (1) show general users the limitation and possible uncertainty of the retrieved urban LST from the single thermal channel of Landsat sensors; (2) emphasize efforts which should be done for the quantitative applications of Landsat data; and (3) understand the potential challenges for the continuity of Landsat observation (i.e., thermal infrared) for global change monitoring, while several climate data record programs being in progress.
自1972年发射第一颗卫星以来，陆地卫星计划已连续运行了四十多年。陆地卫星计划收集的大量数据档案使学术界和社会都受益匪浅。陆地卫星传感器提供的具有相对较高空间分辨率的热成像，适用于监测城市热环境。关于这一主题的出版物不断增加，特别是在过去十年中，这表明陆地卫星数据在监测城市热环境中的使用越来越多。城市热环境通常由地表温度（LST）来描述。然而，从陆地卫星数据中定量准确地估算地表温度仍然是一个挑战，尤其是在城市地区。本文将讨论城市地表温度反演的主要挑战，包括城市地表发射率、大气校正、辐射定标和验证。此外，我们还将讨论陆地卫星观测定量应用连续性面临的一般挑战。这些挑战主要源于陆地卫星7号增强型专题绘图仪（ETM+）的扫描行校正器故障以及不同传感器之间的通道差异。基于这些调查，关注点在于：（1）向一般用户展示从陆地卫星传感器的单个热通道反演得到的城市地表温度的局限性和可能的不确定性；（2）强调在陆地卫星数据定量应用方面应做出的努力；（3）了解在几个气候数据记录计划正在进行的情况下，陆地卫星观测（即热红外）连续性在全球变化监测方面面临的潜在挑战。
