关键词: 郑州, 城市化, 暴雨, WRF模拟

Abstract: In recent years, the urbanization in Zhengzhou region developed rapidly. In order to analyze the impact of urban underlying surface expansion on the weather process, especially torrential rain process, the coupled WRF3.7/UCM model was used to simulate the torrential rain process occurring on 22 May 2017, and the impact of Zhengzhou urbanization on this process was analyzed. Based on the changing of underlying surface, 3 sensitivity tests were set: original USGS land cover data (scheme 1), land cover data changing the 5 districts in downtown of Zhengzhou into urban (scheme 2), land cover data changing all Zhengzhou city into urban (scheme 3). The results indicated that the WRF3.7/UCM model could represent the temporal and spatial distribution characteristics of this torrential rain process quite well. With the effect of urbanization, the total precipitation in Zhengzhou region increased, while the effect was different in different areas, which was more significant in the center and upwind of Zhengzhou. On one hand, urbanization caused the increasing of sensible heat flux, boundary layer height and vertical velocity, which promoted the accumulation of unstable energy, and contributed to the occurrence and development of heavy rainfall. On the other hand, urbanization caused the decreasing of water evaporation and latent heat flux, and changed the distribution of water vapor flux. The water vapor condition became unfavorable to the occurrence and development of rainfall in some areas.

Key words: Zhengzhou, urbanization, torrential rain, WRF simulation