P49 Circulation Structures Leading to Propagating and Non-propagating Heavy Summer Rainfall in Central North China

Sun, Wei, MIRS, National Space Science Center, Chinese Academy of Sciences, Beijing, China, Jian Li, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Rucong Yu, LASW, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing, China, Weihua Yuan, LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China

For heavy rainfall over the mountain area, whether it lasts in the local mountains or propagates downstream to the plains has long been a difficult issue in central North China. This study discovers that the evolutions of these rainfall are closely connected to upper-tropospheric temperature anomalies. When upper-tropospheric warm (cold) anomalies dominate North China (the Japan Sea) and stretch down to lower layers, low-level convergence and strong convection maintain in the west, and rainfall persist over the mountains constituting a non-propagating process. But when upper-tropospheric cold (warm) anomalies dominate the west (east) of 110 degrees E and stretch down to lower layers, the lower moisture tongue and strong convections move from the mountains to the plains, and the mountain rainfall propagate to the plains constituting a propagating process. In a further experiment using WRF model, by only exchanging the temperature field in the upper troposphere of these two types of rainfall, the original non-propagating rainfall move from the mountains to the plains as the propagating one, and vice versa. Results of this study indicate that upper-tropospheric temperature has significant influence on rainfall evolution, and focus on its characteristics could provide beneficial references in the forecast of rainfall propagation.