摘要
In this paper, an unusual rainfall in Beijing that occurred on 4 September(‘9.4') 2015 is studied to clarify the reasons for such a strong rainfall in autumn. It was indicated that various factors, including stationary westerlies disturbance(i.e. low in the west and high in the east), forward-titling trough,warm shear line, unstable stratification and convective available potential energy release, low level jet as well as a series of mesoscale convective systems produced the strong rainfall. Ordinarily, this situation is uncommon in autumn.
In this paper, an unusual rainfall in Beijing that occurred on 4 September（＇9.4＇） 2015 is studied to clarify the reasons for such a strong rainfall in autumn. It was indicated that various factors, including stationary westerlies disturbance（i.e. low in the west and high in the east）, forward-titling trough,warm shear line, unstable stratification and convective available potential energy release, low level jet as well as a series of mesoscale convective systems produced the strong rainfall. Ordinarily, this situation is uncommon in autumn.
基金
supported by the National Key Basic Research Program of China[grant number 2012CB417201]
the National Natural Science Foundation of China[grant number 41375053]
