Study on impact of urbanization on regional hydrological elements: a case study of Zhengzhou City

In recent years, with the acceleration of urbanization, the hardening of the surface had a certain impact on the evolution of regional hydrological elements.Taking Zhengzhou City as the study area, this research combined remote sensing imagery with field measurement data and employed methods such as mathematical statistics and correlation analysis to examine the patterns of land use, precipitation and temperature in Zhengzhou City from 2000 to 2020, as well as the correlations between land use and these two variables.The results indicated that: from 2000 to 2020, Zhengzhou′s land use was dominated by cropland and construction land.In terms of land use dynamics, the order was construction land > water bodies > grassland > forest land > cropland.The average annual increase in construction land was 59.59 km², and the comprehensive land use intensity index showed an upward trend.Three precipitation indicators, annual maximum daily precipitation, annual precipitation, and annual maximum three-day precipitation all showed a downward trend in both urban and suburban areas.The differences between urban and suburban areas were all positive and showed an upward trend, with urban areas being more prone to heavy rain and higher-intensity precipitation events than suburban areas. Both annual maximum and minimum temperatures showed an upward trend.The daily average maximum and minimum temperatures in the urban area were both higher than those in the suburban area.The average temperatures in July and January were both on an upward trend, with the urban area showing a faster rate of increase than the suburban area.From 2000 to 2020, precipitation in Zhengzhou City was negatively correlated with land use intensity, while temperature was positively correlated with land use intensity.