Extending Climate Data Records to the Qing Dynasty
Extending climate data beyond the instrumental record is important since it provides a context of recent changes within the back drop of long-term climate. The rainy season is an important climate feature over Eastern China where anomaly in either its timing or length can lead to adverse economic and social consequences. BER-sponsored researcher W.C. Wang has examined records of daily precipitation description at Beijing and Shanghai contained in Memos-to-Emperor during the Qing Dynasty. They provide a unique source to extend the rainy season information to 1736. The information together with the instrument measurements since 1875 in both cities reveals significant inter-annual and decadal variations of the beginning and ending dates, and length of the rainy season. The analysis further reveals that, on the decadal time scale, the length of the rainy season increased in Shanghai since 1961 with more frequent extreme rainfall events, but decreased in Beijing since 1975 with persistent dry conditions. This pattern of changes was not seen in any other periods of the data, in particular during 1736-1820 when both cities showed an increase in the length of the rainy season.
Wang W.C., Ge Q., Hao Z and Zheng J., Zhang P., and Sung S., 2008: Rainy Season at Beijing and Shanghai since 1736. J. Meteor. Soc. Japan, 86, 827-834.