【摘要】 通过对一次陆地爆发性气旋的数值模拟与湿位涡的诊断分析发现 ,气旋的爆发与湿位涡的平流关系密切 ,气旋的发展并不是在湿位涡中心位于气旋上空时才开始 ,而是当湿位涡中心位于气旋的后部 ,并在 2 0 0 h Pa以下有明显的倒圆锥形下伸区时 ,才有利于气旋的发展。当湿位涡中心位于气旋上空时 ,气旋发展开始减慢。湿位涡局地变化的大小与水平方向位涡梯度的大小有关。湿斜压位涡负值区的上下贯通与气旋发展也有明显的关系。更多还原

【Abstract】 In this paper,numerical simulations and diagnostic analyses of moist potential vorticity for a land explosive cyclone are performed.We find that the burst of the cyclone is close associated with the advection of moist potential vorticity.The development of cyclone doesn’t begin at the time when a center of moist potential vorticity is above the cyclone, but at the time when the center is behind the cyclone. In addition,the existence of a distinct inverted conical subsidence zone below 200hPa is also favorable to the development.The large value zone of moist potential vorticity in lower layers has an obvious connection with activities of a lower front.The local change of moist potential vorticity connects with the magnitude of horizontal moist potential vorticity gradient.The variation of the negative/positive values of baroclinic moist potential vorticity below 850hPa is in good correspondence with the development of the cyclone.更多还原