全球变化知识资源中心

Natural hazards such as floods and droughts occur frequently in southwestern China and have occurred more frequently in recent years, which has caused and will continue to cause serious damage to ecosystems and human lives and property. A full knowledge of the probability of hydro climatic variables is essential for the prevention and mitigation of natural hazards in return. Based on historical archives, atlases and other documented data, a sequence of graded drought and flood disasters covering the period 1250-2000 in Wuzhou City, southwest China, was reconstructed. Then, a correlation coefficient (-0.79, p < 0.01) was established between the sequence of grades and the measured annual precipitation from 1961 to 2000; using this correlation and the sequence of grades from 1250 to 2000, the annual precipitation record (from 1250 to 2000) was reconstructed and extended. Finally, we compared the reconstructed annual precipitation to the measured values from 1961-2000 to evaluate the efficacy of this method. The results show that the reconstructed precipitation sequence is credible, with a high correlation coefficient (0.84, p < 0.01) and a low relative bias (-1.95%). The reconstructed results indicate that the annual precipitation in Wuzhou City increased continuously during the 13-15th century and the 18-19th century and decreased during the 16-17th century and the 20th century. These results are expected to be useful for the prevention of flood and drought impacts and for understanding climate change.