【摘要】 为进一步了解华南暴雨的形成机理,利用MM5模式输出的高时空分辨率资料,对“98.5”华南暴雨的总涡源、视热源和视水汽汇进行了诊断分析。诊断结果表明:总涡源场与涡度场对应一致,高值中心位于降水上空,正的总涡源柱中心预示了涡度柱将继续发展;在组成总涡源各项中水平绝对涡度平流项和扭转项是负贡献,垂直涡度平流项和散度项为正贡献;降水区与视水汽汇和视热源高值区对应一致,视水汽汇和视热源有峰值相伴,说明凝结潜热给系统提供了发展的能量;地面涡动通量和各层的次网格尺度涡动使高层冷却,低层加热,有利于降水系统中对流发展;在组成视热源和视水汽汇各项中均为垂直项起主要作用,充分说明了在暴雨发生过程中强上升运动具有重要作用;强烈的垂直上升运动将水汽带到了高层,云水场的发展与视水汽汇有着一致性,在视水汽汇达到极值时,除冰晶外,云水场各物理量中心高度达到极值,部分物理量的强度也达到最大。更多还原

【Abstract】 In order to understand the heavy rainstorm processes of South China in pre-summer flood season,the total vorticity,the apparent heat source and the apparent moist source were diagnosed.The results are as following: The total vorticity was similarwith the vorticity,their centers were both above the precipitation.The positive total vorticity meant the vorticity would be developing.In the components of the total vorticity,the vection of the absolute vorticity and the distortion term were the negative contribution,and the others were opposed.The rain was under the centers of the apparent heat source and the apparent moist source,and they had similar configuration that meant the latent heat was the energy source producing this rainfall.The sub-grid turbination was favorable to the development of the convection.In their components,both the vertical terms were dominating.The vapor was transferredto high levels by the vertical motion.The cloud water fields was corresponded with the apparent moist source.Not included the ice,when the apparent moist source was the biggest,the altitude of the other fields also reached the top,and the intensity of some is maximum.更多还原