第八届全国城市气象学术论坛

65 / 2021-08-22 15:52:36

地表属性,人为热排放及气候变化对区域热环境影响的数值模拟研究

WRF-UCM,城市热岛,气候变化,下垫面属性,格点人为热

Urban expansion and climate change can considerably influence the regional thermal environment. In this study, high-resolution land cover type and vegetation parameters, anthropogenic heat (AH) emission and future climate change scenarios are incorporated into Weather Research and Forecasting (WRF)/Urban Canopy Model (UCM) model. Their impacts on atmospheric thermal environment in a Chinese megacity, Hefei, are investigated by seven numerical experiments and a dynamical downscaling technique. It’s found that land use (LU) change results in warming and drying in the urban environment, while the rural environment is becoming colder and wetter. The latter is caused by the increasing vegetation coverage in rural areas during the past years. The contribution of LU change to the summer urban heat island (UHI) intensity is about 0.91℃, and the AH emission is about 0.18℃. The number of discomfort hours varies greatly in different years, but for the same year, the fluctuation of the heat index (HI) threshold has little effect on discomfort hours. It is found that LU change increases the urban discomfort hours by about 42 hours, and AH emission increases those by about 16 hours averaged for July from 2017 to 2019. The relative humidity under Representative Concentration Pathways (RCP) 8.5 scenario does not decrease with the increase of air temperature due to the increased water vapor content. Moreover, future urban thermal comfort would reduce under the background of global warming.