Study on urban rainstorm pattern of short-duration double-peak

At present, researches on urban short-duration rainstorm patterns mainly focus on single-peak rainstorm patterns, and rarely involve double-peak rainstorm patterns, or convert double-peak patterns into single-peak patterns directly, even ignore the impact of double-peak patterns, which directly affects the urban flood planning and early warning and rescue. To scientifically and rationally deduce the urban short-duration double-peak rain pattern, this paper proposes a new function fitting rain pattern method by constructing double-peak virtual rain peak rainfall and virtual rain peak coefficient, based on the idea of convert double-peak to single-peak, then revert to the double-peak, directly deducing the double-peak rain pattern. The results show that (1) The rain pattern derived by the function fitting rain pattern method (FFRPM) can effectively improve the accuracy of the double-peak rain pattern and is also more practical; (2) The fitting degree of function fitting rainfall pattern and actual rain pattern is more than 90%, accounting for 80%, the fitting degree of main and secondary peak rainfall is more than 90%, with an average of about 95%; the accuracy of the main and secondary peak positions is also relatively high; (3) Compared with the P&C rain pattern method, whether the overall accuracy or local peak rainfall, the FFRPM has the higher accuracy, especially more accurate on rain peak rainfall.