The researchers studied rainfall patterns in the subtropical monsoon marginal zone. They used global precipitation data to look at how monsoon intensity and area affect rainfall. They found that areas with small changes in the monsoon boundary had increasing rainfall, while areas with larger changes had decreasing rainfall. The Pacific decadal oscillation and other climate patterns weakened the monsoon circulation, leading to less rainfall in the North Pacific. The East Asian summer monsoon zone is getting drier, especially in eastern Inner Mongolia and the Loess Plateau, while the Qinghai-Tibet Plateau is getting wetter. Overall, the study helps us understand how monsoon regions are responding to global changes.