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.

Based on the experiments with the Coupled Forecast System version 2 (CFSv2), the mechanism by which the Madden-Julian Oscillation (MJO) modulates the North Atlantic Oscillation (NAO) is investigated. To isolate the cyclic MJO heating with an eastward propagation over the Indian Ocean and western Pacific, three sets of experiments are conducted with spatio-temporal varying heating added to the model’s internally generated heating. The results suggest that the anomalous MJO heating over the Indian Ocean, rather than the western Pacific, dominates the formation of the NAO anomaly in the following 10-20 days. The MJO heating triggers a westward propagation of the storm track that influences Europe, complementing the eastward pathway of influence via the North Pacific. Both pathways contribute to an enhanced storm track over the North Atlantic and the positive NAO anomaly. The Eurasian pathway is less important for the formation of the negative NAO anomaly.