Research on the characteristics of urban rainstorm pattern in the humid area of Southern China: a case study of Guangzhou City

Extreme precipitation occurs frequently because of hydrological variability, resulting in humid cities facing serious waterlogging problems. Previous studies about rainstorms had emphasized on spatial-temporal distribution characteristics, but rarely on rainfall pattern (RP). With a typical humid city in southern China, such as Guangzhou City in Guangdong Province as the research object, hourly precipitation data from January 2009 to October 2014 are collected from five meteorological stations in Guangzhou. The data are counted and classified by fuzzy mode recognition method according to seven typical rainfall patterns (STRP) and the Huff rainfall pattern (Huff RP). Subsequently, the distributive characteristics of urban rainstorm pattern (RSP) are analyzed. The main results obtained are as follows: (1) annual rainstorm days have high positive correlation with rainfall days, and the annual amount of rainstorm contributes to 7.5-50.5% of the annual total rainfall in Guangzhou, (2) large-scale rainfall is highly possible to occur in Guangzhou, (3) most rainstorms in Guangzhou are unimodal, of which the frontal peak is more than 70%, and (4) STRP are appropriate for RSP division in Guangzhou City.