On the event-based extreme precipitation across China: Time distribution patterns, trends, and return levels

The preceding and succeeding precipitation (P-S-P) of a precipitation extreme often contribute to flooding initiated by the extreme event itself. In this study, the concept of event-based extreme precipitation (EEP), defined as a precipitation event (daily precipitation ≥ 1 mm for successive days) having at least one daily precipitation extreme (daily precipitation ≥ the 99th percentile), is proposed to consider P-S-P of daily extreme precipitation. Further, the time distribution patterns, trends, and return levels of EEPs across China are analyzed based on a 0.5 × 0.5° gridded precipitation dataset covering 1961-2016. The data demonstrate the EEP concept, that multi-day EEP with daily extreme precipitation occurring late in the event is predominant in China except for the Northwest where single-day EEP prevails. Over west China, EEP is increasing and becomes more temporally concentrated. In the lower Lantsang River, along the southeast coastline and on the Hainan Island, the 20- and 50-yr return levels of EEP would exceed 300 and 400 mm, respectively. Moreover, global warming possibly induces more single-day EEPs in the Northwest. The EEP concept may help guide attempts to manage extreme precipitation on event basis, which is particularly useful for regions characterized by long-lasting extreme precipitation.