【摘要】 受西风带蒙古低空冷涡、台风低压和副热带高压的共同作用，１９９４年７月１１－１２日控制我国中纬度地区的大气环流形势发生了一次由纬向型向经向型的转变。７月１２日北京出现了大暴雨。作者在天气学分析的基础上，应用中尺度数值预报模式进行数值试验，探讨天气系统的相互作用，分析北京地区特大暴雨触发机制。更多还原

【Abstract】 nder the influence of westerly low level cold vortex,trOPical storm and subtropical high,the atmospheric circulation at the midlatitude of China changed from latitude pattern to longitude pattern in July 11 to 12 in 1994.Using the mesoscale numerical model (MM4) from PSU/NCAR, numerical experiments have been made to analyse the high level jet,low level jet,water vapor transport and westerly cold air,in order to study the interaction of weather systems and trigger off machenism of heavy rain.更多还原