CGCM projections of heavy rainfall events in China

This paper discusses projections of heavy rainfall events in China during the 21st century based on daily precipitation data from the Fourth Assessment Report's (AR4) Coupled General Circulation Models (CGCM). Results show that all three experimental scenarios (scenarios A2, A1B, and B1) project consistent changes in frequency and intensity of heavy rainfall at the end of 21st century. In the regions of Northeast China and North China, there are no significant changes in frequency but there are remarkable increases in intensity of heavy rainfall, indicating that enhanced intensity is the main contributor to increased ratios of heavy rainfall to total annual precipitation in these regions. In regions of the lower reaches of Yangtze River and South China, increases in the amount of heavy rainfall are closely associated with increased frequency and increased intensity. Projected frequencies of heavy rainfall at the end of 21st century increase by 30.9 similar to 56.6% in the Yangtze River and 35.9 similar to 50.2% in South China compared to the period of 19801999, and projected intensities increase by 1.0 similar to 5.7% and 2.8 similar to 6.3%, respectively. Additionally, the ratios of heavy rainfall to total annual precipitation increase by 2.3 similar to 5.4% in the Yangtze River and 1.8 similar to 3.8% in South China. The significant increases of heavy rainfall ratios indicate that as the climate warms, heavy rainfall events are expected to increase at rates that are much faster than increases in total precipitation amounts, indicating that China will experience increased amounts of flooding. These results are substantially consistent among the three IPCC (Intergovernmental Panel on Climate Change) scenarios.