The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.
LUO Zhexian2, ZHOU Xiuji1 & GAO Shouting3 1. Chinese Academy of Meteorological Sciences, Beijing 100081, China
The rainfall over the Yangtze River val- ley during flood seasons (June to July) shows both interannual and decadal variations. The rainfall has been increasing since 1990, showing a decadal sig- nal. The variations of rainfall are influenced by the multi-scale interactions in the atmosphere-ocean coupled climate system. The rainfall, SST, and cir- culation are analyzed with the Chinese 160 station data, and other observational/reanalysis data, re- spectively. The separation between the interannual and decadal variations is carried out. The key areas affecting the Yangtze rainfall are the western Pacific warm pool on the interannual time scale and the EINO3 area on the decadal time scale, respectively. The circulation anomaly associated with the interan- nual variation occurs in the upper troposphere whereas that associated with the decadal variation appears in the lower troposphere.
