Increased Occurrence and Intensity of Consecutive Rainfall Events in the
China's Three Gorges Reservoir Area under Global Warming
Consecutive Rainfall Events (CREs) are important triggers of geological
hazards like landslide downhill and mudslide in the Three Gorges
Reservoir area (TGR), China. These hazards are not only potential risks
for the effective storage capacity of the reservoir but also threats of
the safety of the reservoir’s Great Dam. The future changes of CREs’
occurrence and intensity are analyzed by using the projection
experiments from twenty models attending the Coupled Model
Inter-comparison Project phase 5 (CMIP5) under three different
representative concentration pathways (RCP2.6, RCP4.5 and RCP8.5).
Spring and fall are focused on, during which CREs are most frequent.
Considering a common overestimate of rainy days number in the
state-of-the-art models, a new approach is developed to define CREs
based on the percentile of rainfall distribution in observations. The
approach yields a similar CREs climatology in models to that in
observations, and thus is used to identify CREs in models. The results
based on multiple model ensemble (MME) and model spread comparison
suggest a significant increase in spring and an overall decrease in fall
in CREs’ occurrence under all three scenarios. As for the intensity, it
is projected to intensify both in spring and fall. Particularly, the
higher the emission scenario, the greater the spring accumulated
rainfall amount during a single CRE. These results imply an increasing
risk of geological hazards in the TGR in the future.