青藏高原东部冰雹形成机理的数值模拟

Numerical Simulation of Hail Formation Mechanism in East of the Tibetan Plateau

利用中国科学院大气物理研究所发展和改进的三维冰雹云模式,对青藏高原东部甘肃省玛曲县的一例冰雹云过程进行了模拟研究。结果表明:玛曲冰雹云中冰雹胚胎以霰胚为主;在地面降水中,固态降水占降水总量的46%,而霰占固态降水的65%,霰主要靠撞冻雨水和云水增长;雹云中存在较弱的过冷雨水累积带,累积带的维持时间也很短,累积带中的过冷雨水有利于雹块的增长,但不起主要作用;雹块的增长主要是通过雹撞冻云水,其次是撞冻雨水增长。

Using a 3D cloud model developed and improved by Institute of Atmospheric Physics, Chinese Academy of Sciences, a hailstorm occurring in Maqu County, Gansu Province in east of the Tibetan Plateau, is simulated. The model results show that the hail embryos are mainly graupel particles. Solid phase precipitation accounts for 46% of ground precipitation amount and graupel-fall is 65% of solid phase precipitation. Graupel particles grow by accretion with rainwater and cloud water. Accumulation zone of supercooled water is present in this hailstorm, however, it is very weak and its maintain time is short. The supercooled raindrop in the accumulation zone is favorable to hailstone growth, but it does not play a main role. The hailstones grow mainly through collection cloud water and accretion with graupel, and secondly accretion with rainwater.