中国古历经朔数据的恢复及应用

中国元代的《授时历议》保存了44部古历的推朔参数及比验资料．借助古代朔望计算方法：1）恢复了诸历行用初年的天正经朔数值；2）修正了史载的错误数据．3）根据Meeus方法计算出经朔的理论值，并由此确定古历经朔的推步精度；4）尝试应用这些数据考察地球自转长期变化，得出日长变化为1．8ms／cy．

Recovery and Application for the Mean New Moon Data Derived from Chinese Ancient Calendars

Shoushi Liyi, an ancient treatise for reviewing Shoushi calendar in Yuan dynasty of China, recorded the parameters and comparing results for new moon calculation of 44 ancient Chinese calendars. By investigating their computing methods of these calendars, it has 1) recovered the values of mean new moon in their initial executing years and in this lunar month the winter solstice should be included; 2) modified the errors existed in ancient records; 3) derived the theoretical values of mean new moon from the Meeus method in order to obtain the accuracy of calendar's calculation for mean new moon; 4) attempted to apply these data to study the secular variation of Earth's rotation and educed the change rate of LOD (length of day) is 1.8ms/cy.