Projecting Spatial Patterns of Flood Hazard: Recent Climate and Future Changes over Yangtze River Basin

Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961-1990) and future (2011-2100) under SRES B2 scenario. The results showed the mean annual rainstorm days over the basin by the near-term, mid-term and long-term would increase from 3.9 days to 4.7,4.9 and 5.1 days, and the mean annual maximum 3-day precipitation from 122 mm to 143, 146 and 149 mm, respectively. The flood hazard of the basin would become more severe, especially in the middle and lower reaches. Flood hazard grade 5 by the near-term, mid-term and long-term would extend from 10.99% to 25.46, 28.14 and 29.75%, respectively.