Sensitivity of precipitation statistics to urban growth in a subtropical coastal megacity cluster

• Published in: Journal of environmental sciences (China) 2017-09, Vol.59 (9), p.6-12
• Main Authors: Holst, Christopher Claus, Chan, Johnny C.L., Tam, Chi-Yung
• Format: Article
• Language: English
• Subjects: Cities - statistics & numerical data; Climate; Environmental Monitoring - methods; Micro climate sensitivity; Rain; Urban precipitation; Urbanization; Urbanization - trends; 人类活动; 城市发展模式; 城市增长; 城市群; 敏感性; 热带沿海; 统计; 降水量
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2017.01.004

This short paper presents an investigation on how human activities may or may not affect precipitation based on numerical simulations of precipitation in a benchmark case with modified lower boundary conditions, representing different stages of urban development in the model. The results indicate that certain degrees of urbanization affect the likelihood of heavy precipitation significantly, while less urbanized or smaller cities are much less prone to these effects. Such a result can be explained based on our previous work where the sensitivity of precipitation statistics to surface anthropogenic heat sources lies in the generation of buoyancy and turbulence in the planetary boundary layer and dissipation through triggering of convection. Thus only mega cities of sufficient size, and hence human-activity-related anthropogenic heat emission, can expect to experience such effects. In other words, as cities grow, their effects upon precipitation appear to grow as well.