摘要
The famous weather records of the Palace Museum contain the daily weather records about overcast,fairness,rain hour and wind direction in Beijing (1724-1903), Nanjing (1723-1793), Suzhou (1723-1810), Hangzhou (1723-1773) and so on. These data have been used to reconstruct the precipitation and to discuss a rainy spell. The direct solar radiation would be reduced in an overcast day and continuous rain is often caused by a
