A Detectable Anthropogenic Shift Toward Intensified Summer Hot Drought Events Over Northeastern China

This study investigates the influence of external forcings on the various summer hot drought events (SHDEs) over northeastern China (NEC). SHDEs are represented by the probability-based index (PI), which considers precipitation and temperature anomalies. The results show that SHDEs over NEC increased from 1961 to 2005, and the experiments for historical forcing (ALL), increased greenhouse gases emission forcing (GHG), and anthropogenic forcing (ANT) can largely reproduce the spatial and temporal features of the trends of SHDEs over NEC. Based on the optimal fingerprinting method, the impact of increased anthropogenic activities can be detected at the 90% confidence level. In addition, the attributable changes of PI in response to GHG and ANT forcings resemble the observation, implying that the increasing trends of SHDEs over NEC are primarily attributed to the increased anthropogenic activity. Furthermore, the occurrence probability of SHDEs over NEC will be further increased under different Representative Concentration Pathways in the future. Additional strict control regulations on GHG emissions are thus suggested to mitigate its impact on regional climate changes.