【摘要】 利用常规气象资料和NCEP再分析资料,结合宁夏业务化的中尺度数值预报模式MM5输出产品,对2006年7月14日发生在贺兰山东麓宁夏的极值暴雨过程从降水特征、环流背景、影响系统、强降水落区及物理量特征等方面进行了分析。表明:此次极值暴雨是在2006年第4号台风"碧利斯"与副热带高压系统的相互作用、中β尺度低值系统影响和地面静止锋的触发下爆发的。强降水落区位于200 hPa青藏高压前部西北气流辐散区与500 hPa西南气流、700 hPa西南或偏南低空急流、850 hPa偏东气流三股气流辐合区相重叠区,中β尺度低值系统的右前侧与湿焓平流最强的区域。对流层高层干冷空气下侵是强降水的主要触发机制之一。非地转湿Q矢量与强降水落区有良好的对应关系,对短时强降水天气具有较好的描述能力和预报指导意义。更多还原

【Abstract】 Using NCEP reanalyzed data and meteorological data,and products of Ningxia mesoscale numerical forecasting model(MM5),the rainstorm occurred at the east part of Helan mountain was analyzed.Result shows: the heavy rain area was located at the overlap district between northwest airflow divergent area at 200 hPa and the convergent area of three airflows.The three airflows are southwest airflow at 500 hPa,south or southwest lowlevel jet at 700 hPa and east airflow at 850 hPa.The heavy rain also was located in the area of the highest value wet enthalpy advective and rightfront of meso-β scale low pressure system.The interaction between typhoon Bilis and subtropical high over west Pacific provided plenty of instability energy and water vapor,forced the cold air to move toward northeast.The invasion of dry and cold air from troposphere is one of the main causes of heavy rain.Nongeostrophic wet Q-vector corresponds to heavy rain area very well,it can be used to predict shorttime heavy rain process.更多还原