The changing climate and intensifying human activities have made an impact on the hydrological processes in the upper Yangtze River (UYR), but quantifying their effects remains uncertain. This study used the Budyko framework to investigate the response of runoff (Q) to climate change and human activities during 1956–2017 and evaluate the impacts of human activities, including land use/cover change, water use, dam construction, and vegetation change, on watershed characteristic. Results show that climate change is the dominant driver of Q variations in the Wujiang River (WJR), Jialing River (JLR), and Jinsha River (JSR) watersheds, with contributions of 58.6%, 66.9%, and 67.6%, respectively. However, in Mingjiang River (MJR) and UYR watersheds, human activities contribute more to Q variations with 55.2% and 51.2%, respectively. Human activities play important roles in variation of watershed characteristics, and they can explain 22%, 26%, 36%, 25%, and 53% of the watershed character change in UYR, WJR, JLR, MJR, and JSR, respectively. This study conducts a comprehensive analysis of the causes of Q change in UYR, and provides a new perspective to explore the effects of specific human activities on watershed characteristics.

The Pacific–Japan (PJ) pattern traditionally refers to the meridional dipole mode of rainfall and the low‐level circulation over the tropical western North Pacific and mid‐latitude East Asia. However, recent studies have reported that the PJ pattern can also affect the Indian summer monsoon (ISM) via the anomalous circulation over the North Indian Ocean. We summarize the currently available PJ indices and re‐examine the linkage between the PJ pattern and the ISM. We found that the only PJ indices that are significantly correlated with rainfall in southern India are the two indices containing signals of the Maritime Continent. The Maritime Continent rainfall can also stimulate circulation anomalies in the North Indian Ocean, thereby strengthening the PJ–ISM linkage. When the signals associated with the Maritime Continent are removed, the PJ–ISM linkage becomes weak and insignificant. The PJ indices should be chosen carefully when studying the climatic impacts of the PJ pattern.

Western North America (WNA) experienced an unprecedented heatwave from late June to early July 2021, which lies far outside the historical range. Based on the model outputs from Coupled Model Intercomparison Project Phase 6, we find that the likelihood of a heatwave over WNA similar to the 2021 one increases with global warming. Such a heatwave is projected to occur more frequently with increased extreme temperature and shortened return period. It means that a rare event in the current climate will be a more common event in a warmer climate, especially under a high‐emission scenario like the Shared Socioeconomic Pathways 585 (SSP5‐8.5). Moreover, we show a large expansion of areas over WNA that will break the 2021 record in the future with an increasing level of emission scenario. Nevertheless, some heatwave records west of the Rocky Mountains are still difficult to break, highlighting the specific extremity of the 2021 WNA heatwave.

A new teleconnection pattern (the BEAP) across the Bay of Bengal‐East Asia‐Pacific region in boreal summer is revealed in this study using mainly ERA‐Interim reanalysis data from the European Centre for Medium‐Range Weather Forecasts. The BEAP index (BEAPI) is defined as the signed sum of standardized apparent moisture sinks at five centers along the pathway. Correlation analysis of the apparent heat sources and apparent moisture sinks has verified the existence of the BEAP teleconnection. Variations in BEAP can affect precipitation anomalies resulting from the anomalous moisture transport and the antiphase surface temperature variation. Wave flux analysis has verified the Rossby wave propagation route that originates around the central Bay of Bengal and extends across North China to the West Pacific. La Niña‐type sea surface temperature anomalies (SSTAs) appearing simultaneously in the same season can excite a positive BEAP pattern by enhancing convection over the Bay of Bengal, while El Niño‐type SSTAs have the opposite effect. Significant correlation between the BEAPI and the SSTAs can last from early summer to early winter. Numerical experiments confirm the BEAP teleconnection pattern and the associated physical processes.