摘要
本文对一次引起夏季华北暴雨的锋生过程进行了研究。在诊断分析的基础上,我们采用十层准拉格朗日有限区域模式对此个例进行了48小时的模拟,并对模拟输出结果进行解释与再次诊断。表明:(1)夏季高原东侧有时两支气流交绥很清楚,温度对比明显,与梅雨锋的情况很不相同,这在夏末尤其如此。这种温度对比区虽比冬季弱,但是,与夏季天气系统的发展及降水是有关系的。(2)模拟结果与实际观测资料是很相似的,再现了两支气流形成切变线的三维结构、移动与演变,并模拟出了在对流层中存在着深厚的24小时变温区;模拟发现,一条东北-西南向的锋生区自西向东移动并加强,最大值集中于华北,其主要贡献来源于锋生函数的变形项;模拟的涡度场再现了北槽南涡的结合以及正涡度最大值区与强锋生区迭加的过程,这有可能预示未来中尺度系统的发展。(3)模拟中放入美国NMC的地形,同时对侧边界方案进行了试验,表明地形与侧边界有重要影响。
A frontogenetical process of OOGMT 15- 00GMT 17 August, 1981 has been discussed. Results are summarized as follows. (1 )During this period, cold air invaded North China from middle-high latitudes and, at the same time.the warm air originating from the SE of the Tibetan Plateau already extended Northwards and reached the Korean Peninsula by OOGMT 17 August. Strong interaction between cold and warm air occurred in North China, then, a cold front formed and intensified. This situation is quite different from Baiu front. (2) A ten - level quasi - lagrangian limited area numerical model with terra in of the Tibetan Plateau was used to simulate the process successfully. In our experiments, different schemes of terrains and lateral boundary conditions were tested. It is shown that the results of simulation experiments are very sensitive to some schemes .( 3 ) Frontogenetical function, F-d/ dt , was calculated at different standard pressure surfaces, respectively. It is found that the maxima of frontogenetical function appeared ahead of the trough at 700 hPa and the deformation term of frontogenetical function probably contributes greatly to the development of mesoscale systems near frontal zone in North China.
出处
《大气科学》
CSCD
北大核心
1991年第5期40-50,共11页
Chinese Journal of Atmospheric Sciences
关键词
锋生
中尺度
预报
数值模拟
Mesoscale system
Numerical weather prediction, Frontogenesis .
