| The plague is one of the climax natural disasters which is company with the human beginning to end. Researching the relationship between plagues in the history and natural environment, can be use for reference for the prevention and control of infectious disease, which is the need of the times. Based on the historical materials of plagues, climate changes and natural disasters in the Ming Dynasty, this thesis studies on the spatial-temporal distribution of plagues and the environmental mechanism,mainly using spatial analysis and mathematical statistics methods.The plagues in the Ming Dynasty, on the dynasty distribution, the Chongzhen dynasty is the most serious, followed by the Wanli and Jiajing dynasties, and the Jianwen and Hongxi dynasties are the slightest; on the seasonal distribution, the spring and summer are the high incidence seasons of plagues, followed by the autumn,and the winter is the slightest; on the trends and cycles, the general trend is on the rise, the number of plague counties adds 9.5 every ten years, and there exist two scales of the fluctuation cycles which are 100 years and 50 years, experiencing about 5 "light-serious" shift cycles under the 100 years cycle, and about 8 "slight-serious" shift cycles under the 50 years cycle; on the province distribution, the plagues decrease from the northeast to the southwest in the whole, the most serious provinces locate in the northeast, including the South Zhili, North Zhili, Zhejiang, etc, the plague of the Guangdong, Guangxi, Yunnan, Guizhou and Sichuan which locate in the southwest are general slight; on the county distribution, there are totally 1009 counties exist plages, and the Wu county in the Sough Zhili has the highest frequency of plagues, to the 8.3%, followed by the Daxing and Wanping in the North Zhili, both are 7.94%, there are totally 542 counties have no plague, the frequency is 0; on the cold-hot spots distribution, the hot spots of plagues mainly locate in the three regions in the northeast, the cold spots of plagues mainly locate in the three regions in the southwest; there are 10 extra-serious plague year in the Ming Dynasty, which can be summarized to 5 extra-serious plague processes.On the whole country, the trends of cold and warm change of climate and plagues are contrary in the Ming Dynasty, the fluctuation cycles are close and show significant negative correlation, the plague counties decrease significantly when the climate changes warm, increase when cold. The cause-effect relationship between climate change and plagues can be modeled by the regression equation y=-1.456x-0.577, the standardized value of plague counties adds 1.456 when the standardized value of temperature decreases 1,and the change of plague counties can be explained to 23% by the cold and warm change of climate. On the regional, the trends of cold and warm change of climate and plagues are contrary in the North China area, the fluctuation cycles are close and show low negative correlation, the cause-effect relationship between climate change and plagues can be modeled by the regression equation y=-0.63 lx, the standardized value of plague counties adds 0.631 when the standardized value of temperature decreases 1, and the change of plague counties can be explained to 39.6% by the cold and warm change of climate; the trends of cold and warm change of climate and plagues are contrary in the East China area, the fluctuation cycles are close and show low negative correlation, the cause-effect relationship between climate change and plagues can be modeled by the regression equation y=-0.429 x-0.001, the standardized value of plague counties adds 0.429 when the standardized value of temperature decreases 1, and the change of plague counties can be explained to 15.4% by the cold and warm change of climate; the trends of cold and warm change of climate and plagues are all contrary in the Central China, South China and Southwest China ares, all show weak negative correlation, but don't have the statistical significance.On Eastern area, the trends of dry and wet change of climate and plagues are contrary in the Ming Dynasty, the fluctuation cycles are close and show low negative correlation, but don't have the statistical significance. One the regional of the Eastern area, the dry and wet change of climate and plagues both show weak negative correlation in the Huabei and Jianghuai area, and both don't have the statistical significance, the trends of dry and wet change of climate and plagues in the Jiangnan area shows low negative correlation, and have the statistical significance.On the relationship of plagues and floods of the Ming Dynasty, the temporal distribution shows significant positive correlation, the correlation coefficient is 0.739. Specifically, the increasing trends have statistical significance of totally positive correlation, the correlation coefficient is 1, the fluctuation cycles have no statistical significance. The spatial distribution also shows significant positive correlation, the correlation coefficient is 0.613, the plagues and floods both decrease from the coastal provinces to inland provinces, the centers of plagues and floods are almost coincide. The cause-effect relationship between plagues and floods can be modeled by the regression equation y=0.421x-20.961, the ten-year plagues counties adds 0.421 when the ten-year floods counties increases 1, and the change of plagues counties can be explained to 33.1% by the change of floods counties.On the relationship of plagues and droughts of the Ming Dynasty, the temporal distribution shows high positive correlation, the correlation coefficient is 0.861, the plagues are also serious when droughts are serious, vice versa. Specifically, the increasing trends have statistical significance of high positive correlation, the correlation coefficient is 0.998, the fluctuation cycles also have statistical significance of high positive correlation, the correlation coefficient is 0.844. The spatial distribution also shows significant positive correlation, the correlation coefficient is 0.657, the plagues are also serious where droughts are serious, vice versa, the centers of plagues and droughts are almost coincide. The cause-effect relationship between plagues and droughts can be modeled by the regression equation y=0.546x-18.230, the ten-year plagues counties adds 0.546 when the ten-year droughts counties increases 1, and the change of plagues counties can be explained to 74.1% by the change of droughts counties.On the relationship of plagues and locusts of the Ming Dynasty, the temporal distribution shows significant positive correlation, the correlation coefficient is 0.681, the plagues are also serious when locusts are serious, vice versa. Specifically, the increasing trends have statistical significance of total positive correlation, the correlation coefficient is 1, the fluctuation cycles also have statistical significance of significant positive correlation, the correlation coefficient is 0.541. The spatial distribution also shows significant positive correlation, the correlation coefficient is 0.555, the plagues are also serious where locusts are serious, vice versa. The cause-effect relationship between plagues and locusts can be modeled by the regression equation y=0.705x+10.724, the ten-year plagues counties adds 0.705 when the ten-year locusts counties increases 1. and the change of plagues counties can be explained to 46.4% by the change of locusts counties.On the relationship of plagues and earthquakes of the Ming Dynasty, the temporal distribution shows significant positive correlation, the correlation coefficient is 0.643, the plagues are also serious when earthquakes are serious, vice versa. Specifically, the increasing trends have statistical significance of total positive correlation, the correlation coefficient is 1, the fluctuation cycles have no statistical significance correlation. The spatial distribution also shows low positive correlation, the correlation coefficient is 0.390, both the plagues and earthquakes are serious in the Jingshi area of North Zhili, Taiyuan are in the center of Shanxi, Yingtian area in the east of South Zhili, and Xian area in the southwest of Shaanxi. The cause-effect relationship between plagues and earthquakes can be modeled by the regression equation y=0.383x+6.354, the ten-year plagues counties adds 0.383 when the ten-year earthquakes counties increases 1, and the change of plagues counties can be explained to 29% by the change of earthquakes counties.The environmental mechanisms of plagues can be interpreted to be the environmental elements which influence the plagues, the influence extent and the action mechanisms. There are five main natural environmental elements which influence the plagues of the Ming Dynasty, including the cold and warm changes of climate, floods, droughts, locusts and earthquakes. The influence extent of the five environmental elements can be ordered by "droughts (74.1%)> locusts (46.4%)> floods (33.1%)> earthquakes (29%)> cold and warm changes of climate (23%) " from high to low. The mechanisms of environmental elements influence the plagues, essentially reflected from influencing the three aspects of infection sources?transmission routes and susceptible population, if multiple disasters coincident, there will be severe plagues. |
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