【摘要】 利用纬向平均的局地经向环流模式,对1984年南海地区4月28日～5月31日每日两个时次的局地平均经向环流进行模拟。模拟结果与观测结果吻合,反映出1984年南海夏季风形势的建立是一个经历反复的过程。此外,用诊断分析的方法通过计算各动力和热力强迫因子对季风经向环流的贡献,发现驱动1984年南海夏季风经向环流的首要因子是潜热加热项,主要由北部凝结加热,南部蒸发冷却的经向不均匀加热场分布使得潜热加热对环流的作用为正。温度垂直对流输送项的作用次之,该项的分布在南海北部的值为正、南部值近似为零,这种分布形势也使该因子能单独引起一个正季风环流。第三大因子是纬向温度平流输送项,在南海地区北部有暖平流,南部冷平流的温度平流分布形势对季风环流也起正的作用。而对季风中断期的因子分析表明:潜热加热及纬向温度平流的作用与正季风环流建立期完全相反,温度垂直对流的正作用也大大减弱。更多还原

【Abstract】 Most of 68 simulated local meridional circulations (twice a day from 00 UTC April 28 to 12 UTC May 31,1984) agree very well with the 搊bserved?circulations over the South China Sea. These results show that the establishment of 1984 summer monsoon was a slow process with reversed circulation during May 4 to May 6. The forced anti-Hadley circulations at 00 UTC April 28 and 00 UTC May 17 (representing respectively the onset times accepted by different research groups) were mainly associated with latent heat releasing. The second and third important factors are associated with adiabatic processes and zonal temperature advection.更多还原