对华北中尺度低压个例的数值模拟及敏感性试验

选取典型个例，用MM4模式对华北中尺度低压进行模拟分析以及敏感性试验。检验了MM4模式对行星边界层中尺度系统的预报能力。通过调整风场，温度场，气压场与地形的配置关系，设计多种试验方案，并讨论了气流与山脉交角大小，冷暖平流对华北中低压的影响，结果表明，气流与山脉交角大，低层暖平流或弱冷平流，对华北中低压形成是有利的。反之，则不利于华北中低压出现。通过对天气观测事实和模拟试验结果进行分析，提出对华北中低压有重要作用的大尺度背景条件。

A Numerical Simulation and Sensitivity Tests of the Meso-scale Low in North China

A simulation of typical weather event about meso-scale lows occurred in PBL over the North-China Plains and a series of its sensitivity experiments are carried out by using PSU/NCAR's MM4 mesoscale model,which examines the MM4's forecast capability for the meso-scale systems in PBL.It analyzes the impact of angles between airflow direction,mountain axis,and warm(cold) advection on the mesolow in North China by adjusting the matched patterns of terrain with wind,temperature and pressure fields.The result shows that the bigger the angle with a warm (or weak cold) advection in the lower layer,the more favourable for the generation of the macro-scale circulation,which play an important role in generating the mesolow,are put forward in line with the observed weather facts and the result of modelling tests.