摘要：In this paper a seasonal model is proposed to deal with weekly agricultural seasonal patterns in which neither the length of the seasonal period nor the magnitude of the seasonal effects remain the same over time. To model this heterogeneous seasonal behaviour, the seasonal effect at a season is defined as a function of the proportion of the length of the seasonal period elapsed up to this season, and the seasonal pattern is modelled by means of evolving splines. The methodology is illustrated for weekly Canary tomato prices.
