The researchers used a regional climate model to simulate summer precipitation in China from 1951 to 2000. They compared their simulations with actual observations and found that the model performed well in capturing the average rainfall patterns. However, it struggled to accurately represent the spatial distribution of precipitation anomalies, with better results in some regions than others. The model also showed decadal variations in its results, with the 1960s and 1990s being more stable than the 1970s and 1980s. Overall, the model had difficulty reproducing observed decadal variations in precipitation during certain time periods.