NUMERICAL STUDY OF COLD AIR IMPACT ON RAINFALL REINFORCEMENT ASSOCIATED WITH TROPICAL CYCLONE TALIM(2005):I.IMPACT OF DIFFERENT COLD AIR INTENSITY
DONG Mei-ying1,CHEN Lian-shou 2,LI Ying 2,CHENG Zheng-quan 3,ZHENG Pei-qun 4(1.Zhejiang Institute of Meteorological Sciences,Hangzhou 310008 China;2.State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081 China;3.Guangdong Provincial Meteorological Observatory,Guangzhou 510080 China;4.Zhejiang Provincial Meteorological Observatory,Hangzhou 310017 China)
In 2005,significant rainfall reinforcement and severe disaster was induced by tropical cyclone(TC) Talim after it made landfall on the east of China.Observational analyses show that it has relationship with cold air intrusion.For investigating the impact of cold air intensity,we make use of Weather Research and Forecasting(WRF) model,the synthesizer of NCEP/NCAR reanalysis data and Japan regional spectral model data,to carry out numerical experiments.Results show that rainfall reinforcement occurs in all experiments.Different intensity of cold air can modify the rainfall distribution and intensity significantly.In the rainfall center,the increment maximum of rainfall is twice as large as that of the minimum.Moderate cold air intrusion may result in the strongest rainfall reinforcement.Different cold air intensity can lead to different motion of low-level convergence lines and fronts.There is a good relationship between the rainfall region and the eastern part of the front.On one hand,strong cold air weakens the TC intensity by its intrusion into the TC center and results in weak convergence and a convergent zone and a rain band shifted southward.On the other hand,weak cold air reduces the convergence and moves the convergent zone and rain band northward.Moderate cold air intrusion maintains strong low-level convergence and high-level divergence,keeping strong upward motion over certain regions.Consequently,the rain band begins to stagnate and rainfall reinforces abruptly therein.
【Fund】： Meteorological Technology Special Opening Projects of Zhejiang Province (kf2010002);; National Public Welfare Special Project of China (GYHY201206006);; Planning Project for Key National Fundamental Research (2009CB421504);; National Natural Science Foundation of China (41105062 40675033);; Meteorological Technology Planning Projects of Zhejiang Province (2011ZD01)
【CateGory Index】： P426.6
【CateGory Index】： P426.6