left:
         lat   lon    PC          gh
       <num> <num> <ord>       <num>
    1: -22.5   0.0   PC1 0.017593184
    2: -22.5   2.5   PC1 0.017585293
    3: -22.5   5.0   PC1 0.017580330
    4: -22.5   7.5   PC1 0.017581851
    5: -22.5  10.0   PC1 0.017592958
   ---                              
20156: -90.0 347.5   PC5 0.004206307
20157: -90.0 350.0   PC5 0.004206307
20158: -90.0 352.5   PC5 0.004206307
20159: -90.0 355.0   PC5 0.004206307
20160: -90.0 357.5   PC5 0.004206307

right:
           date    PC          gh
         <Date> <ord>       <num>
  1: 1990-01-01   PC1  0.12015851
  2: 1990-02-01   PC1  0.11921023
  3: 1990-03-01   PC1  0.11905844
  4: 1990-04-01   PC1  0.11914120
  5: 1990-05-01   PC1  0.11874389
 ---                             
356: 1995-08-01   PC5  0.07093237
357: 1995-09-01   PC5 -0.01593794
358: 1995-10-01   PC5 -0.01926659
359: 1995-11-01   PC5  0.26030288
360: 1995-12-01   PC5  0.15063041

sdev:
      PC          sd           r2
   <ord>       <num>        <num>
1:   PC1 1524593.818 9.997635e-01
2:   PC2   15617.405 1.049075e-04
3:   PC3    8444.272 3.066998e-05
4:   PC4    6126.190 1.614247e-05
5:   PC5    5176.628 1.152611e-05
