时间变量有误，楼主需要仔细查看...

stl(x, s.window, s.degree = 0,
    t.window = NULL, t.degree = 1,
    l.window = nextodd(period), l.degree = t.degree,
    s.jump = ceiling(s.window/10),
    t.jump = ceiling(t.window/10),
    l.jump = ceiling(l.window/10),
    robust = FALSE,
    inner = if(robust)  1 else 2,
    outer = if(robust) 15 else 0,
    na.action = na.fail)

对变量x的说明如下：
x  univariate time series to be decomposed. This should be an object of class "ts" with a frequency greater than one.

能解释一下后面那句话的意思吗：“This should be an object of class "ts" with a frequency greater than one.”

请用过 stl 函数的朋友说一下这个函数中的x应该怎么定义？

x变量必须是ts时间序列属性，并且超过一次频率、亦重复时间（月份、周日等变量）
This should be an object of class "ts" with a frequency greater than one.

例如：
            Sun Mon Tue Wed Thu Fri Sat
week 1
week 2
...

或
         Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1920
1921
1922
...

感觉STL分解s.window的设置比较不确定，论文中是说的该值≥7，且为奇数。如果不考虑趋势项 还可以用STL吗？