Regional Changes in Precipitation Concentration, Seasonality and Intermittency in China

ABSTRACT The unique topography of China, combined with the large‐scale atmospheric circulation patterns, results in uneven precipitation distribution across different climatic zones of China, namely the temperate continental zone (TCZ), temperate monsoon zone (TMZ), subtropical monsoon zone (SMZ), tropical monsoon zone (MZ) and mountain plateau zone (MPZ). Although more frequent, intense, severe and longer‐lasting precipitation is projected to occur with global warming, changes in the precipitation seasonality and intermittency remain poorly understood, particularly across various climatic zones of China. We assess regional changes in precipitation concentration using multiple indices, including the daily concentration index (CI), monthly precipitation concentration index (PCI), seasonality index (SI) and precipitation intermittency represented by the burstiness and memory (B and M) of precipitation, across the five climatic zones in mainland China from 1961 to 2020. The variability of precipitation concentration and intermittency is further teleconnected to large‐scale atmospheric circulations using correlation analysis and lagged regression models. Results show that precipitation in TMZ and SMZ occurred more concentrated, as indicated by a higher value of CI, because summer precipitation accounts for most of the annual precipitation. SMZ and TCZ exhibit more even seasonal precipitation than other regions. There is a significant increasing trend in summer precipitation and annual total precipitation in the SMZ, along with decreasing trends in spring and autumn, suggesting an increase in precipitation seasonality as indicated by the increasing PCI. Increasing trends in winter precipitation are detected across all climatic zones, indicating a reduced risk of winter drought in China. Most parts of TMZ and SMZ are likely to experience an increase in the frequency of heavy rain events in the future, with the upward trend of B exceeding 0.05%. At the same time, colder regions in MPZ might experience more regular rainfall with a negative value of B . Correlations between the precipitation indices and large‐scale indices suggest that large‐scale atmospheric circulations play a significant role in the change of precipitation patterns. Specifically, the El Niño–Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) have potentially strong negative effects on the precipitation pattern in SMZ and MZ with nearly all the precipitation indices showing negative correlation coefficients while in TCZ, M is mainly influenced by Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO) and NAO, as suggested by high correlations. These findings enhance our understanding of precipitation characteristics across five climatic zones in China and provide valuable information for mitigating disasters associated with extreme precipitation.