干旱区生态环境知识资源中心

Collection and arrangement of the historical records of climatic changes and environment evolution, especially in the aspect of calamities, are made on the history documents of past 1500 years about Hai’an region, Jiangsu Province. There existed two obvious flooding-drought frequently-occurring periods: one was from 1550 AD to 1850 AD and another was 1000 AD to 1200 AD. The period of 1550 AD to 1850 AD is interrupted by two relatively arid and cold climatic periods: one was from 1630 AD to 1700 AD and another was 1750 AD to 1820 AD. The main characteristic of the calamity periods is that they occurred by turns, and sometimes, both drought and flooding occurred in the same year. The instability of the climatic changes in the Little Ice Age may be the main reason of the frequently-occurring flooding and drought in Hai’an region. Research results also show that the frequently-occurring periods of flooding and drought is in close relationship with the solar activity, and therefore, occurrence of the flooding and drought may be in relation with the intensity of the solar activity. This hypothesis may need further study in the future.