image: Horizontal distribution of universal thermal climate index in ℃ at 2-meter-off ground at 10 a.m. july 1st 2021, higher value indicates more heat stress.
Credit: ©Science China Press
This study is led by Dr. Xiaoran Guo and Dr. Chao Yan (both from Institute of Urban Meteorology, China Meteorological Administration). A fast urban micro-meteorology model was developed and applied over the central Beijing region in summer during a large outdoor event. In comparison with conventional weather forecast methods, the main feature of this model lies in the fine spacial structures of wind, air temperature, humidity and human comfort index revealed by the simulation, which is adequate to capture the shapes of local green belts, water surfaces and 3-D buildings. With these urban morphology resolved, their blockage effects on wind fields and sun lights are calculated as well as the evaporations over certain land type. To realize fast simulation, the wind fields around building cluster were constructed according to statistical relationships and empiracal parameterizations, which largely improve the computational efficiency comparing with traditional CFD methods. To quantify the comprehensive influences of weather and environment on human physiological process, universal thermal climate index was calculated and visualized as a main product for the weather service.
Taking the simulated horizontal distribution of human comfort index as an example, at 10 a.m. july 1st 2021, there were cool areas at the west sides of each building hidden in their shadows, while the east sides were generally under higher heat stress, partly due to the weak wind within building’s lee-side cavity zone. In contrast, through the evaporation processes, the hot stresses were considerably reduced by water surface while effectiveness of vegetation were limited. Through model verification, their results were generally in good agreement with measurements.
See the article:
Guo X, Yan C, Miao S. 2023. A rapid modeling method for urban microscale meteorology and its applications. Science China Earth Sciences, 66(10): 2224‒2238
Journal
Science China Earth Sciences