seasonalityn.季节性差价seasonaladj.季节的；依照季节的；周期性的seasonal water shortage季节性缺水Seasonal freezing areas季冻地区seasonal index forecast季节指数预测seasonal dynamic change季节动态seasonally frozen layer季节冻结层seasonal frozen regions季节冻土seasonal freeze thawing季节性冻融seasonal characteristic季节性seasonal dummy variable季节效应seasonal cycle forecast季节周期预测