Study of Atmospheric Predictability Based on Periphery Theory

The system periphery （＂jieke＂ in Chinese） is defined as a part of the system and is adjacent to its environment. The periphery is an in- termediary agent between the system and its environment, and has two functions： defending system itself and exchanging with the environment. Generally, the periphery is defined on space dimension. We will investigate the periphery from the time dimension, and study a time jieke based on set theory viewpoint; initial values and forecast lead in weather forecast are clarified. Further predictability of weather forecast on the basis of periph- ery theory is defined; its calculation formulae are given, with which computing for day-to-day forecast were carded out. The results have been com- pared with present researches of atmospheric predictability, and it shows advancing the predictability study. Most interesting is that atmospheric pre- dictability possesses rule of gold ratio 0.618, and it is found firstly in research of weather and climate predictability.