ABSTRACT: Spatio-temporal dynamics of urban heat island (UHI) and other spatial temperature variations were studied for a 17 yr period (2002-2018) in the mid-sized (193000 inhabitants in 2019) coastal city of Turku in south-western Finland. The study was based on GIS data and 30 min interval air temperature observations from 52 observation sites in the city and its surroundings. Correlation and regression analyses, image interpretation and various GIS methods were used to investigate temperature dynamics and associated factors on a diurnal, monthly and seasonal basis. The results showed relative cooling and warming trends of certain areas as well as fluctuating and random variation of the coldest and warmest regions, respectively. Relative cooling trends were observed in semi-urban and urban areas that remained unchanged during the study period. Relative warming trends were most common in semi-urban areas where urbanization and construction of new buildings occurred rapidly. Fluctuating variation was mainly related to variation in weather conditions, especially the severity of winter and related sea-ice extent on the archipelago south-west of the city. The UHI intensity showed a slight, albeit statistically significant, intensifying trend of 0.11°C per decade. Our findings demonstrate the dynamic nature of spatio-temporal intra-urban temperature differences, a fact that should more actively be taken into account in climate-related urban planning in general.

中文翻译：

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芬兰高纬度沿海城市图尔库空间温差变化趋势及不规则变化

摘要：研究了芬兰西南部中型（2019 年居民 193000 人）沿海城市图尔库 17 年（2002-2018 年）的城市热岛 (UHI) 时空动态和其他空间温度变化. 该研究基于 GIS 数据和来自城市及其周边地区 52 个观测点的 30 分钟间隔气温观测结果。相关性和回归分析、图像解释和各种 GIS 方法用于研究昼夜、月和季节的温度动态和相关因素。结果表明，某些地区的相对降温和升温趋势，以及最冷和最暖地区的波动和随机变化。在研究期间保持不变的半城市和城市地区观察到相对降温趋势。相对变暖趋势在城市化和新建筑建设迅速发生的半城市地区最为常见。波动的变化主要与天气条件的变化有关，特别是冬季的严重程度和城市西南部群岛的相关海冰范围。UHI 强度显示出每十年 0.11°C 的轻微但具有统计学意义的增强趋势。我们的研究结果证明了城市内部时空温差的动态性质，这一事实应该在与气候相关的城市规划中得到更积极的考虑。尤其是城市西南部群岛冬季的严重程度和相关的海冰范围。UHI 强度显示出每十年 0.11°C 的轻微但具有统计学意义的增强趋势。我们的研究结果证明了城市内部时空温差的动态性质，这一事实应该在与气候相关的城市规划中得到更积极的考虑。尤其是城市西南部群岛冬季的严重程度和相关的海冰范围。UHI 强度显示出每十年 0.11°C 的轻微但具有统计学意义的增强趋势。我们的研究结果证明了城市内部时空温差的动态性质，这一事实应该在与气候相关的城市规划中得到更积极的考虑。