Climate driven trends in London's urban heat island intensity reconstructed over 70 years using a generalized additive model
Climate driven trends in London's urban heat island intensity reconstructed over 70 years using a generalized additive model
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DOI：
10.1016/j.uclim.2021.100990
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发表时间：
2021-09-30
期刊：
影响因子：
6.4
通讯作者：
Blair, G. S.
中科院分区：
文献类型：
--
作者：
Bassett, R.;Janes-Bassett, V.;Blair, G. S.
长期的城市热岛（UHI）观测是不常见的，即使有，通常也无法区分气候变化的驱动因素和城市扩张;这两个驱动因素都没有被独立对待。我们克服了这一限制，使用一个广义的添加剂模型学习的变化，在中央伦敦气象站（圣詹姆斯公园）在10年的观测期（2010-2019年）的城市热岛强度（UHII）。然后，我们使用该模型重建70年（1950-2019年）的每月夜间UHII变异使用ERA 5再分析数据作为参考UHII计算和预测。我们发现UHII时间序列（月平均最大UHII为1.4-2.9摄氏度）的季节性和年度性变化相当大。应用极值分析的时间序列，我们表明，每月平均最大UHIIs可能超过2.75摄氏度每11年一次。考虑到大多数研究观察或模拟UHII的时间不到一年，它们可能会歪曲UHII的变异性。尽管如此，尽管转向更温暖的背景气候，伦敦的UHII在整个分析期间（1950-2019年）没有显著变化。我们在这项研究中创建的数据驱动方法很容易转移到其他城市。
Long-term urban heat island (UHI) observations are uncommon and where available, are generally unable to distinguish changing climate drivers from urban expansion; neither driver is treated independently. We overcome this limitation using a generalized additive model to learn the variability in UHI intensity (UHII) at a central London weather station (St James's Park) over a 10-year observation period (2010-2019). We then use the model to reconstruct 70 years (1950-2019) of monthly night-time UHII variability using ERA5 reanalysis data both as a reference in UHII calculation and for the predictors. We find considerable variability both seasonally and annually within the UHII time series (monthly mean maximum UHIIs are 1.4-2.9 degrees C). Applying extreme value analysis to the time series we show that monthly mean maximum UHIIs are likely to exceed 2.75 degrees C once every 11 years. Considering that most studies observe or model UHIIs for less than a year, they will likely misrepresent this UHII variability. Nevertheless, despite moving to a warmer background climate, London's UHII has not significantly changed across the period of analysis (1950-2019). The data-driven methods we create in this study are easily transferable to other cities.