Due to the influence of climate and topography

Shenzhen has experienced frequent short-term rainfall and urban flood disasters

resulting in serious economic losses. Research on the short-term rainfall and tidal situation in Shenzhen has important practical significance for urban flood control and drainage. Based on the rainfall data from Xili Station and tidal level data from Chiwan Station in Shenzhen from 1978 to 2019

the Gumbel Copula function is selected through Copula function optimization to construct the joint distribution of the annual maximum 1-hour rainfall and corresponding period tidal level

and the annual maximum 1-hour rainfall and corresponding period tidal level. The Clayton Copula function is used to construct the joint distribution of the annual maximum tidal level and its corresponding period rainfall. Meanwhile

a combined risk probability model of short-term rainfall and tidal level in Shenzhen is established to calculate and analyze the co-occurrence risk probability and flood prevention risk probability encountered during the recurrence periods of rainfall and tidal waves of 10a

20a

50a

100a

and 200a years. The results show that the Copula function can fit the joint distribution of rain and tide encounters in Shenzhen well. The probability of flood prevention risk encountered by rain and tide is much higher than the probability of co-occurrence risk

and with the increase of recurrence interval

the probability of co-occurrence risk encountered by rain and tide and flood prevention risk both decrease.