Impacts of urban heat island intensities on a bifurcating thunderstorm over Beijing
Publication Date
5-1-2024
Document Type
Article
Publication Title
Urban Climate
Volume
55
DOI
10.1016/j.uclim.2024.101955
Abstract
To gain the insight into the impacts of different urban thermal conditions on precipitation, a series of simulations that modified the surface sensible heat from building is performed during a thunderstorm passage over Beijing. The UHI intensity changed from 0.8 to 2.2 °C with the increase sensible heat. Results showed that: (i) Under weak UHI conditions (≤1.4 °C), it is the urban dynamical effect that played the dominant role. The surface flow was blocked by the urban rough surface, inducing updrafts around the central urban area (CUA) and downdraft over the CUA. As the thunderstorm passed, its convergence line broke over the CUA. The precipitation thus bifurcated; (ii) Under strong UHI conditions (≥1.8 °C), it is the urban thermal factor that played the dominant role, overshadowing the urban dynamical impacts which still existed. The intensified UHI led to a more organized UHI circulation, with stronger updrafts over the CUA. When the storm arrived, the pre-existing updraft and convergence was conducive to convection initiation and enhancement. The precipitation thus concentrated over CUA and strengthened. Employment of a cooling tower scheme improved the simulated precipitation. This study thus represents an initial attempt to differentiate urban thermal and dynamic impacts on thunderstorms.
Funding Number
42330608
Funding Sponsor
National Natural Science Foundation of China
Keywords
Precipitation, UHI, Urban dynamical conditions, Urban impacts, Urban thermal conditions
Department
Meteorology and Climate Science
Recommended Citation
Jingjing Dou, Robert Bornstein, Jianning Sun, and Shiguang Miao. "Impacts of urban heat island intensities on a bifurcating thunderstorm over Beijing" Urban Climate (2024). https://doi.org/10.1016/j.uclim.2024.101955
