增长模在热带地区发展的分析研究

ANALYSIS AND STUDY OF THE GROWTH MODE BREEDING DEVELOPING IN THE TROPICAL AREAS

利用T63L9全球谱模式对制作集合预报的增长模繁殖法(BGM)在热带地区的适用性进行研究,分析了在热带地区扰动增长的机理。设计与物理过程、积云对流参数化方案及湿物理过程有关的3个敏感性试验及1个控制试验。为了讨论不同物理过程对BGM生成扰动的影响,定义扰动动能变化率对试验结果进行分析。结果表明:在热带地区积云对流强盛区内风场扰动能够快速增长。扰动增长机制在热带地区与中高纬地区有本质区别,热带地区扰动的发展主要受物理过程的作用,其中模式积云对流及湿物理过程对扰动中快速增长的部分起着至关重要的作用。中高纬地区扰动发展与背景场的斜压不稳定有关。

The applicability of the Breeding Growth Method （BGM） in tropical areas is studied by using T63L9 global spectral model in this paper, and the mechanism of the mode growth in tropical areas is also analyzed. Three sensitivity experiments and one control experiment are designed with physical processes, cumulus convective parameterization schemes and wet physical processes. In order to discuss the impact of different physical processes on the disturbances generated from the BGM, the change rate of disturbance kinetic energy is defined as a criterion to analyze the experiment results. The results showed that in strong cumulus convection zones of the tropics, wind disturbance can grow rapidly. Essentially different from the mechanism of disturbance growth in the high latitudes, that of the tropical area is mainly affected by physical processes--including cumulus convection and wet physical processes, which play a vital role in the fast-growing disturbance. The disturbance growth in the high latitudes is related with baroclinic instability in the background.