Projected changes in temperature and precipitation extremes over the Yangtze River Basin of China in the 21st century

摘要

Projections of changes in climate extremes are important in assessing the potential impacts of climate change on societal and natural systems. We analyze future projections of climate extremes derived from an ensemble of coupled general circulation models (CGCMs) contributing to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4), under a range of emission scenarios. The extremes are described by seven indices based on temperature and precipitation (HWDI, TN90, CDD, RIO, R5D, SDII, and R95T). The region of our focus is the Yangtze River Basin (YRB) in southern China. Results show a longer duration of heatwave over YRB in the 21st century than today, particularly in the headstream area. More frequent warm nights are also projected in the region. The increases of these temperature extremes under A2 and A1B scenarios are more pronounced than in B1. The change patterns of CDD and RIO are less uniform in the region compared to the other indices. Heavy precipitation events for single days and pentads are projected to increase in their intensity over the YRB. In addition, a larger fraction of the total annual precipitation is projected to occur during heavy precipitation events, i.e. events that exceed the 95th percentile.