南宋时期(1127-1279年)至少有81年发生过疫灾,疫灾频度53.29%。朝代上以宁宗、高宗、孝宗三朝的疫灾最为频繁;季节上以春夏季节为疫灾高发期,秋冬季节疫灾较少发生;趋势上疫灾频度略有下降趋势,但表现为2个波长为70年的波动周期,十年疫灾指数曲线呈"W"型,疫灾广度的年度变化呈脉冲状波动,阶段性特征明显。南宋时期全国至少有241个县发生过疫灾,其中71.37%分布于人口相对稠密的浙西、福建、淮西、浙东、江东、江西、淮东等东部诸路;疫灾严重程度从东部沿海向西部内陆递减,浙西路是全国疫灾最严重的地区;各路疫灾的严重性与人口密度呈显著正相关。从总体分布看,南宋地区的疫灾比金元地区严重,且集中分布于淮河以南今光山-大余一线以东的地区;人口密度高值区也是疫灾频度高值区,长江三角洲是全国疫灾最频繁的地区;当时全国的疫灾中心有今杭州、海宁、湖州、苏州、绍兴等城市。
During period of the Southern Song Dynasty (1127--1279), epidemic disasters occurred in at least 81 years, annually with an average epidemic frequency of 53. 29% In the period, most of the epidemic disasters occurred in between 1127--1162, 1163--1189 and 1195--1224 A.D. The preva- lence of epidemic disasters seemed more preferable in spring and summer, while less preferable in the autumn and winter. The epidemic frequency showed a slightly declined tendency constituted by 2 waved cycles with the length of 70 years. As a whole, the curve of the epidemic index of decade ap- peared to be W--shaped; the annual changes of the epidemic counties of decade and epidemic areas of decade showed in pulse shape fluctuation, which experienced apparent phase characteristic. Spatially, there were at least 241 counties hurt by epidemic disasters, 71. 37% of which distributed in Lu (N) which was located at the eastern region such as Zhexi, Fujian, Huaixi, Zhedong, Jiangdong, Jiangxi, Huaidong with the relatively dense population, from the severity of epidemic disasters, it showed a descending trend from the east coast to the west inland and Zhexi (include nowadays Jiangsu, Zhejiang and Shanghai) had experienced the most severe epidemic disasters. Between epidemic severity and population density in each Lu is there a positive correlation. The general distribution characteristics of epidemic disasters in the period are shown below: epidemic prevalence in the Southern Song adminis- trative regions was more severe than in the Jin and Yuan governed regions, i. e. , epidemic disasters distributed mainly in the region southern to Huai River and eastern to Guangshan city through Dayu city line; the region with the denser population also had the higher epidemic frequency; Yangtze River Delta was the most frequent center of epidemic disasters; nowadays Hangzhou, Haining, Huzhou, Suzhou, Shaoxing cities are then epidemic centers with high frequency.