EGU23-2870
https://doi.org/10.5194/egusphere-egu23-2870
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Understanding the influence of urban form on the spatial pattern of precipitation

Yanle Lu1, Qi Li2, Zhou Yu3, John Albertson4, Xiaodong Chen5, Haonan Chen6, Angeline Pendergrass7, and Leiqiu Hu8
Yanle Lu et al.
  • 1Cornell University, Civil and Environmental Engineering, United States of America (yl2948@cornell.edu)
  • 2Cornell University, Civil and Environmental Engineering, United States of America (ql56@cornell.edu)
  • 3Cornell University, Civil and Environmental Engineering, United States of America (zy328@cornell.edu)
  • 4Cornell University, Civil and Environmental Engineering, United States of America (albertson@cornell.edu)
  • 5Pacific Northwest National Laboratory, United States of America (xiaodong.chen@pnnl.gov)
  • 6Colorado State University and NOAA Physical Sciences Laboratory, United States of America (haonan.chen@noaa.gov)
  • 7Cornell University, Earth and Atmospheric Science, United States of America (a.pendergrass@cornell.edu)
  • 8University of Alabama in Huntsville, Atmospheric and Earth Science, United States of America (leiqiu.hu@uah.edu)

Urban areas are known to modify the spatial pattern of precipitation climatology. Existing observational evidence suggests that precipitation can be enhanced downwind of a city, albeit other locations of precipitation enhancement have also been reported. Among the proposed mechanisms that modify the precipitation, the thermodynamic and aerodynamic processes in the urban lower atmosphere interact with the synoptic conditions and could play a key role in determining the resulting spatial variability of precipitation. In addition, these processes are intricately shaped by urban form characteristics, such as the spatial extent of the impervious land. This study aims to unravel how different urban forms impact the spatial organizations of precipitation climatology under different synoptic conditions. We use the Multi-Radar Multi-Sensor (MRMS) quantitative precipitation estimation data products and analyze the hourly precipitation maps for a selected set of cities across the continental United States from the years 2015 to 2021. Results suggest that a statistically significant downwind enhancement of precipitation does exist in about four-fifths of these cities, while the magnitude is comparable to previous findings. Additionally, we find that the precipitation distribution tends to be more clustered for higher wind speed; the location for precipitation maxima is located closer to the city center under low synoptic winds but shifts towards the urban-rural interface under high wind conditions. The magnitude of downwind precipitation enhancement is highly dependent on wind directions and is positively correlated with the city size for the south, southwest, and west directions. This study provides observational proof through a cross-city analysis that the spatial pattern of urban precipitation can be attributed to the modified atmospheric processes by distinct urban forms.

How to cite: Lu, Y., Li, Q., Yu, Z., Albertson, J., Chen, X., Chen, H., Pendergrass, A., and Hu, L.: Understanding the influence of urban form on the spatial pattern of precipitation, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2870, https://doi.org/10.5194/egusphere-egu23-2870, 2023.