APPLICATION OF PROBABILITY WAVE IN LONG-RANGE SEASONAL PREDICTION

It is discussed that the anomaly in long-range weather is due to the stable sustained circulation.Waves on monthly or seasonal departure maps can essentially be regarded as probability waves which reflect the anomaly distribution of heat sources and sinks on the earth's surface.The persistent stable circulation creats these distributions which serve as persistent disturbance sources and in turn feedback the general circulation with persistent stability in later period.The departure probability waves on a six-month (September-February) chart reflect the anomalous distribution of heat sources and sinks on the underlying surface.The waves north of 30°N move slowly and eastward on the Eurasian Continent against the temperature gradient,while they are stationary south of 30°N.A statistical model is developed to predict the spring-summer temperature and precipitation of next year by using the six-month departure probability wave of last year.During 1982-1985 it was tested in several provinces of northern China with encousaging results.