Most state-of-the-art climate simulation ensembles misrepresent the effects of urbanization on local climate due to computational restrictions, posing a major limitation for urban climate projections. We circumvent this shortcoming by employing the SURFEX land-surface model coupled to TEB (Town Energy Balance) urban canopy model, forced by EURO-CORDEX regional climate simulations. We demonstrate the added-value of CORDEX-SURFEX-TEB compared to EURO-CORDEX in reproducing Lisbon’s temperature observations, halving the bias and improving the PDF matching by ~5%. Furthermore, the proposed framework allows characterizing the urban heat island (UHI) effect. Over Lisbon, the annual-mean UHI was ~+3 ºC (city warmer than rural) during nighttime, and around -0.5 to -1ºC (city cooler than rural) during daytime. The CORDEX-SURFEX-TEB climate projections for Lisbon, under fixed land-use and RCP8.5 scenario, showed a warming of ~+1ºC by 2021-2050 and ~+3.5ºC by 2070-2099. Despite the large multi-model spread, these long-term temperature changes were roughly constant for all hours and for urban and rural environments (corresponding to roughly constant UHI magnitude). Our results also reveal large seasonality of Lisbon’s UHI effect and of long-term warming. Finally, the projections show a striking growth in the number of extreme hot days and nights, respectively nearly tripling and quintupling its current value by 2070-2099.

由于计算上的限制，大多数最新的气候模拟都错误地反映了城市化对局部气候的影响，这对城市的气候预测构成了主要限制。我们通过在EURO-CORDEX区域气候模拟的推动下，采用SURFEX地表模型与TEB（城镇能源平衡）城市雨棚模型相结合的方法来避免这一缺点。我们展示了CORDEX-SURFEX-TEB与EURO-CORDEX相比的附加值，它可以再现里斯本的温度观测值，将偏差减半并将PDF匹配度提高5％左右。此外，所提出的框架允许表征城市热岛效应。在里斯本上空，夜间的年平均UHI为〜+ 3ºC（城市温度高于农村），白天为-0.5至-1ºC（城市温度低于农村）。在固定土地利用和RCP8.5情景下，里斯本的CORDEX-SURFEX-TEB气候预测显示，2021-2050年气温升高约+1ºC，2070-2099年气候升温约+3.5ºC。尽管存在多种模型，但这些长期温度变化在所有小时以及城市和乡村环境中均大致恒定（对应于UHI幅值大致恒定）。我们的结果还显示出里斯本的UHI效应和长期变暖的季节性很大。最终，这些预测显示极端高温白天和夜晚的数量显着增长，到2070-2099年，其当前价值分别将近三倍和五倍。这些长期温度变化在所有小时以及城市和乡村环境中大致恒定（对应于UHI大致恒定）。我们的结果还显示出里斯本的UHI效应和长期变暖的季节性很大。最终，这些预测显示极端高温白天和夜晚的数量显着增长，到2070-2099年，其当前价值分别将近三倍和五倍。这些长期温度变化在所有小时以及城市和乡村环境中大致恒定（对应于UHI大致恒定）。我们的结果还显示出里斯本的UHI效应和长期变暖的季节性很大。最终，这些预测显示极端高温白天和夜晚的数量显着增长，到2070-2099年，其当前价值分别将近三倍和五倍。