Impact of Urbanization on Precipitation Characteristics during Flood Period- A Case Study in Jinan City

Prior multiple studies have shown the impact of urbanization on precipitation, but there is a scarcity of research focusing on the impact of precipitation in the study area at different stages of urbanization.Jinan City was selected as the study area, and the impact of urbanization on precipitation during flood period was investigated by using land use and precipitation data from 1985 to 2022. The characteristics of land use change in the study area was analyzed. Response patterns of rainfall to underlying surface imperviousness was explored. The effects of imperviousness on different precipitation was studied. The findings showed that the urbanization process in Jinan City experienced four stages, with the period from 1995 to 2000 witnessed the most substantial increase in impervious surfaces at an average rate of 114.77 km²/a. When the imperviousness rate exceeded 26%, the rainfall enhancement coefficient was greater than 1.0, and 1.10 when imperiousness exceeded 43%, and potentially 1.20 when imperiousness rate exceeded 60%. The expansion of impervious surfaces notably increased the occurrence of light rainfall.