这是我的数据帧:
jan f m a m j \
2000 -7.894737 22.387006 22.077922 14.5455 15.8038 -3.33333
2001 -3.578947 11.958763 28.741093 5.05415 74.7151 11.2426
2002 -24.439661 -2.570483 1.810242 8.56044 84.5474 -26.9753
2003 14.410453 -10.106570 8.179654 -11.6469 -15.0022 -13.9757
2004 -3.978623 -13.280310 2.558639 -1.13076 12.7156 -4.47235
2005 2.018146 1.385053 9.461930 14.1947 -10.4865 -11.1553
2006 -6.528617 -5.506220 -2.054323 1.39073 7.74041 -0.328937
2007 -1.634891 8.923088 4.951521 -1.33334 3.82215 7.69231
2008 20.539609 0.132377 -3.117323 6.53806 9.99998 16.1356
2009 -3.979917 -9.342541 -23.233634 -26.5963 -27.0396 -4.39528
2010 6.141145 …