中国疫灾的时空分布变迁规律

中国历史上是一个多疫灾的国度,在770BC～AD1911年间,平均每四年就有一年发生疫灾。中国疫灾变化与气候变化关系密切,寒冷期往往为疫灾频繁期,温暖期往往为疫灾稀少期,气候越寒冷,疫灾越频繁,寒冷期越长,疫灾频繁期也越长;3～6世纪的魏晋南北朝寒冷期形成了第一个疫灾高峰,14～19世纪的明清小冰期形成了第二个疫灾高峰;3000年来,随着气候的趋干趋冷,中国疫灾频度也呈长期上升趋势。中国疫灾分布的总体特征是城市重于乡村,京畿地区、人口稠密地区、自然疫源地区、自然灾害频发区为疫灾多发区。区域开发过程和地表人文化过程对疫灾分布变迁趋势有重大影响,3000年来,中国疫灾分布区域有从黄河中下游向外扩展的趋势,重心区域有由北向南、由东向西迁移的趋势。

Changes of the Temporal-spatial Distribution of Epidemic Disasters in 770BC-AD1911 China

Historically China was a country with high epidemic frequency which was as high as 25% during 770BC-AD1911. The changes of the epidemic frequency in historical China had closely corresponded with temperature variations climatically. The high frequency periods of epidemics often occurred in the cold spells whereas the sparse periods usually dropped into the warm spells; the colder the climate was, the more frequent the epidemic was, and the longer the cold spell of climate went on, the longer the climax period of the epidemic lasted. For example, the cold era of the Wei, Jin and Southern & Northern dynasties from the 3rd century through the 6th century was the first epidemic climax, the "little ice age" of the Ming and Qing dynasties from the 14th century through the 19th century formed the second epidemic climax. For the past 3000 years China's epidemic frequency had a long-term increasing tendency due to the increasing older climate trend. The general characters of China's epidemic distribution showed that epidemic prevalence in the cities was more severe than in the countryside, and there were more frequent epidemic disasters in the capital city and its environs, densely populated areas, natural epidemic foci, or frequent natural disaster affected areas. The process of regional development and earth-surface humanization had significant impact on the changes of epidemic geographical distribution, the distributional area of epidemics in China during 770BC-AD1911 was radiated gradually from the middle and lower Yellow River, and the core of epidemics showed a shifting trend both from north to south and from east to west.