Ma Jin, Zhou Ji, Zhang Tao, Tang Wenbin, Liao Yangsiyu, Yang Miao
School of Resources and Environment, University of Electronic Science and Technology of China, Chengdu 611731, China.
School of Resources and Environment, University of Electronic Science and Technology of China, Chengdu 611731, China.
Sci Total Environ. 2024 Nov 1;949:174928. doi: 10.1016/j.scitotenv.2024.174928. Epub 2024 Jul 29.
Surface urban heat island (SUHI) intensity generally determined by satellite-derived clear-sky land surface temperature (LST) has ignored the impacts of cloud coverage and cannot reflect the real SUHI intensity. Only a few studies focus on the effects of this issue based on short-time LST datasets, which could contain non-negligible uncertainties to summarize reliable rules. To investigate the influence, the SUHI intensity (SUHII) clear-sky bias (CSB), which is defined as the SUHII difference between clear-sky and all-weather conditions, was investigated in 35 cities in China, based on clear-sky and all-weather LST datasets from 2003 to 2022. Results show that the two SUHIIs show similar spatial distribution patterns, with stronger SUHIs in southern China at daytime and weaker at nighttime. However, a non-negligible difference can be found between these two SUHIIs, with a SUHII CSB range of -1.43 to 2.27 °C at daytime and - 2.17 to 0.91 °C at nighttime. In terms of intra-annual variation, SUHII CSBs in similar climate regions exhibit similar patterns but different ranges due to their different natural properties. Generally, intra-annual variations of SUHII CSB can be divided into three groups, i.e., "Table Mountain", single peak, and single valley, varying across climate regions and years. The main reason for SUHII CSB was analyzed, i.e., spatial gaps of the data directly caused the SUHII CSB, and the thermal properties and meteorological conditions of the missing pixels affect the magnitude of the SUHII CSB. Taking the urban system as an example, this study has provided evidence of the non-negligible SUHII clear-sky bias to emphasize the importance of using all-weather LST for relevant studies.
通常由卫星反演的晴空陆地表面温度（LST）所确定的城市地表热岛（SUHI）强度忽略了云覆盖的影响，无法反映真实的SUHI强度。仅有少数研究基于短期LST数据集关注了这一问题的影响，而这些数据集可能包含不可忽视的不确定性，难以总结出可靠的规律。为了研究这种影响，基于2003年至2022年的晴空和全天候LST数据集，在中国35个城市中研究了SUHI强度（SUHII）的晴空偏差（CSB），其定义为晴空和全天候条件下SUHII的差值。结果表明，两种SUHII呈现出相似的空间分布模式，中国南方白天的SUHI较强，夜间较弱。然而，这两种SUHII之间存在不可忽视的差异，白天SUHII CSB范围为-1.43至2.27℃，夜间为-2.17至0.91℃。就年内变化而言，相似气候区域的SUHII CSB呈现出相似的模式，但由于其自然属性不同，范围有所差异。一般来说，SUHII CSB的年内变化可分为三组，即“桌山”型、单峰型和单谷型，随气候区域和年份而变化。分析了SUHII CSB的主要原因，即数据的空间间隙直接导致了SUHII CSB，缺失像元的热属性和气象条件影响了SUHII CSB的大小。以城市系统为例，本研究提供了SUHII晴空偏差不可忽视的证据，以强调在相关研究中使用全天候LST的重要性。
