用轴对称的平衡模式对热带气旋发展过程中积云动量垂直混合作用的模拟

A Study of Cumulus Momentum Vertical Mix in Tropical Cyclogenesis Using an Axisymmetrically Balanced Model

引入一个轴对称的平衡数值模式 ,在该模式中考虑积云动量垂直混合等物理过程 ,然后以此模式对热带气旋形成和发展的过程进行了模拟。所作研究表明 ,引入积云动量垂直混合作用之后热带气旋发展更为迅速 ,并且成熟气旋的强度更强 ;在气旋生成的初期 ,积云动量混合的作用并不大 ,只有在气旋发展到了一定阶段 ,积云对流十分旺盛时 ,才会产生较大的作用 ;在空间分布上 ,积云动量垂直混合主要发生在对流层的中低层 ,而高层则相对较弱 ,对热带气旋的影响很小。另外 ,发展成熟的热带气旋其辐散层较厚 ,质量辐合主要集中在边界层 ;热带气旋的内部结构和环流特征造成了各个高度层次上熵的不同分布形态。

We introduce a axisymmetrically balanced model in which cumulus momentum vertical mix is brought into use, and study tropical cyclogenesis by this model. The results show that tropical cyclone develops more rapidly and the mature cyclone is much stronger after cumulus momentum vertical mix is in use. The effects of cumulus momentum mix are evident only when cyclone develops to some extent and cumulus convection is strong. In vertical dimension, cumulus momentum vertical mix is weak in upper layers, so introducing cumulus momentum vertical mix in upper layers has few effects on the development of tropical cyclone.