我国羊肉价格的季节波动特征及替代品价格冲击效应——基于HEGY检验和SVAR模型的实证分析

针对2000—2020年我国羊肉价格出现的波动上升态势，运用HEGY季节单整检验和FDSD季节模型识别羊肉价格的季节波动特征，运用SVAR模型和FEVD、IRF工具分析替代品价格对羊肉价格的冲击效应。结果表明:1)我国羊肉价格波动呈现确定型季节特征和积分型趋势特征。羊肉价格的确定型季节波动特征表现为每年秋、冬季节上涨，春、夏季节下跌，并在春节前后达到涨跌极值，气温因素和节日效应明显；2)猪肉、活鸡和牛肉价格对羊肉价格的当期传递弹性依次为0.010、0.038和0.634；3)猪肉、活鸡和牛肉价格对羊肉价格波动的相对贡献程度为16.4%、5.9%和31.2%；4)分时期看，替代品对羊肉短期价格冲击明显、长期替代关系稳定；5)分品种看，牛肉、猪肉对羊肉的需求替代关系最为明显，但特点不同。羊肉价格对牛肉价格冲击的响应程度高、但衰减速度快；对猪肉价格冲击的响应则具备持续性。固有的季节性消费规律促使我国羊肉价格呈现周期性波动，较强的当期需求替代导致猪肉、牛肉价格对羊肉价格的显著冲击效应。

Seasonal fluctuation characteristics of China's mutton price and the shock effect of substitute price: An empirical analysis based on HEGY test and SVAR model

Aimed at the fluctuation rising trend of China''s mutton price from 2000 to 2020, HEGY seasonal integration test and FDSD seasonal model are used to identify the seasonal volatility feature of mutton price. SVAR model and FEVD and IRF tools are used to analyze the shock effect of substitute price on mutton price. The results show that: 1)The fluctuation of China''s mutton price is generated by the process of deterministic seasonality and integral trend. Mutton price rises in autumn and winter and falls in spring and summer with the extreme values of rise and fall appearing around the Spring Festival, which is mainly caused by the temperature factor and festival effect. 2)The current transmission elasticity of pork, live chicken and beef prices to mutton price are 0. 010, 0. 038 and 0. 634, respectively. 3)The relative contribution of pork, live chicken and beef prices to the volatility of mutton price are 16. 4%, 5. 9% and 31. 2%. 4)In terms of time, the short-term price shock of substitute on mutton is obvious, but the long-term relationship between mutton and substitute is stable. 5)In terms of variety, beef and pork have obvious substitution relationships for mutton, but the characteristics of them are different. The response of mutton price to beef price shock is high, with a fast decay rate at the same time, while the response to pork price shock is long-lasting. The inherent seasonal consumption law makes the China''s mutton price fluctuate periodically, and the strong current demand substitution causes the significant shock effect of pork and beef prices on mutton price.