第八届全国城市气象学术论坛

Urban expansion and climate change can considerably influence the regional thermal environment. In this study, the effects of changes in land cover type and vegetation coverage (referred to as LU for short), gridded anthropogenic heat (AH) emission and future climate change on atmospheric thermal environment in a Chinese megacity, Hefei, were investigated by Weather Research and Forecasting (WRF)/Urban Canopy Model (UCM) model. It was found that the increase of surface sensible heat flux in old urban areas is contributed by AH emission, while that in new urban areas is attributed to LU change. The LU change in new urban areas can lead to the decreased latent heat flux due to the reduction of vegetation coverage and the increase of impervious land surface. The contribution of LU change to the summer UHI intensity is about 0.76℃, and AH emission to that is about 0.17 ℃. The combined effects of LU change and AH emission in old urban areas are greater than those in new urban areas, leading to the changes in daily mean 2-m temperature, 2-m relative humidity (RH) and heat index in old (new) urban areas to be 1.08 ℃ (0.75 ℃), –5.93 % (–4.96 %), 2.77℃ (1.76 ℃), respectively. At the end of the 21st century, the urban air temperature under RCP 4.5 (RCP 8.5) scenario is 0.7 ℃ (3 ℃) higher than that under Current scenario. Both the frequency and intensity of warming in urban areas may increase in the future.

WRF-UCM,城市热岛,气候变化,下垫面属性,格点人为热