A comprehensive framework model for the trend, period and evaluation of the precipitation enhancement effect: TPEM.

In this study, a framework model (TPEM) for evaluating the temporal and spatial variation of urban precipitation is established. TPEM includes seven calculation methods at the same time. Taking the annual precipitation and flood season precipitation data of eight meteorological stations in Zhengzhou, China, from 1960 to 2020 as an example, the trend and period of rain island effect in Zhengzhou are analyzed from the annual and flood season rainfall scale, and the distance method is introduced to quantitatively evaluate the rain island effect. The results show that the rain island effect in the central urban area of Zhengzhou has a sudden increase trend in 1997 and 2004 respectively, and the increasing trend of rain island effect on the scale of annual and flood season rainfall lasts for four and ten years respectively. At the same time, it has fluctuation periods of 8-10a, 16-18a, 3-5a, 17-20a, 5-7a, and 2-3a respectively. The rain island effect in Zhengzhou is concentrated in the flood season. The research can provide a scientific basis for cities to deal with the rain island effect in the future. [ABSTRACT FROM AUTHOR]