RECONSTRUCTION OF ANNUAL WINTER MEAN TEMPERATURE SERIES IN HEFEI AREA DURING 1736-1991 A. D.
合肥地区1736－1991年年冬季平均气温序列的重建

In this paper, we used a new and important historical document, which kept in the National First Historical Archive at the Palace Museum. This is a very systematic and rich climatic proxy document, which mainly records the depth of rainfall-penetration and snowfall. the beginning date and ending date of every rainfall or snowfall process in various areas. We find a good correlationship between annual winter mean temperature (T) and snowfall-days (D) in the Hefei area at the measurmental period, and the regression equation is:T=5. 06-0. 173D.According to the equation just mentioned above, an annual winter mean temperature series was reconstructed based on the snowfall-days during the period from 1736 A. D. to 1911 A.D..Since 1911 A. D. the annual winter mean temperature series in Hefei was supplemented by that in Nanjing and the measurmental value in Hefei. Therefore. a complete annual winter mean temperature series for Hefei region was reconstructed from 1736 A. D. to 1991 A. D..By adopting F statistical test, the reconstructed series of annual winter mean temperature is reliable and consistent. Further analysis indicates that there are three warm periods and two cold periods during the last 250 years in the Hefei area by using optimum division method. The warm periods are 1736-1790 A. D. 1851-1871 A. D. and 1907-1991 A. D. . and the coldperiods are.1791-1850 A. D.. and 1872-1906 A. D. . Comparson of temperature changes in different area in China shows that warm period is in 18th and 20th century. and 19th centuryis a cold period. The cold period of 19th century is the last cold period of modern little ice age.In addition. by analysing the temperature changes in the last 250 years in the Hefei area. the middle of 19th century (nearly 1851-1871 A. D.) is a very obvious warm period, and it can not be found in most areas in China.