******************************************************************* *** Mauna Loa isotopic ratio of atmospheric 13C/12C (permil) *** *** averages of data adjusted to the 15th of each month *** *** *** *** Source: C.D. Keeling, A.F. Bollenbacher, and T.P. Whorf *** *** Carbon Dioxide Research Group *** *** Scripps Institution of Oceanography (SIO) *** *** University of California *** *** La Jolla, California USA 92093-0444 *** *** *** *** March 2005 *** *** *** ******************************************************************* Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ave FitAve 1980 99.999 -7.599 -7.707 -7.642 -7.681 99.999 -7.590 -7.470 -7.441 -7.481 -7.454 99.999 99.999 99.999 1981 -7.569 -7.641 99.999 -7.738 -7.825 -7.761 99.999 -7.491 -7.395 -7.350 -7.464 -7.583 (-7.594) -7.598 1982 -7.585 -7.641 99.999 -7.736 -7.801 -7.642 -7.671 -7.465 -7.392 -7.441 -7.499 -7.619 (-7.598) -7.595 1983 -7.652 -7.603 -7.628 -7.721 -7.862 -7.756 -7.712 -7.580 -7.433 -7.474 -7.601 -7.671 -7.641 -7.648 1984 -7.669 -7.806 99.999 -7.899 -7.898 -7.858 -7.720 -7.659 -7.569 -7.544 -7.605 -7.593 (-7.719) -7.714 1985 -7.650 -7.756 -7.806 -7.748 -7.850 -7.792 -7.678 -7.502 -7.497 -7.598 -7.580 -7.628 -7.674 -7.677 1986 -7.633 -7.726 -7.759 -7.867 -7.830 -7.705 -7.629 -7.518 -7.472 -7.480 -7.536 -7.609 -7.709 -7.706 1987 -7.688 -7.706 -7.774 -7.834 -7.817 -7.849 -7.735 -7.622 -7.569 -7.581 -7.671 -7.664 -7.709 -7.706 1988 -7.772 -7.850 -7.848 -7.949 -7.970 -7.879 -7.769 -7.730 -7.632 -7.616 -7.652 -7.740 -7.784 -7.783 1989 -7.813 -7.856 -7.909 -7.953 -7.940 -7.929 -7.818 -7.707 -7.614 -7.619 -7.733 -7.781 -7.806 -7.809 1990 -7.857 -7.902 -7.973 -8.027 -8.063 -7.933 -7.787 -7.720 -7.612 -7.737 -7.735 99.999 (-7.845) -7.837 1991 -7.747 -7.838 -7.926 -7.956 -7.994 -7.891 -7.821 -7.773 -7.666 -7.652 -7.740 -7.802 -7.817 -7.824 1992 -7.816 -7.860 -7.927 -7.964 -7.989 -7.977 -7.831 -7.731 -7.689 -7.673 -7.772 -7.800 -7.836 -7.829 1993 -7.821 -7.819 -7.909 -7.908 -7.992 -7.902 -7.795 -7.710 -7.601 -7.633 -7.749 -7.811 -7.804 -7.812 1994 -7.876 -7.871 -7.895 -7.976 -8.010 -7.979 -7.840 -7.735 -7.677 -7.699 -7.783 -7.895 -7.853 -7.846 1995 -7.850 -7.889 -7.945 -8.033 -8.058 -8.019 -7.899 -7.784 -7.737 -7.724 -7.795 -7.861 -7.883 -7.888 1996 -7.931 -7.960 -8.023 -8.044 -8.078 -8.078 -7.984 -7.845 -7.757 -7.769 -7.844 -7.897 -7.934 -7.931 1997 -7.936 -7.995 -8.044 -8.096 -8.126 -8.050 -7.967 -7.859 -7.780 -7.746 -7.861 -7.942 -7.950 -7.956 1998 -8.001 -8.018 -8.081 -8.164 -8.189 -8.197 -8.105 -7.971 -7.921 -7.900 -7.956 -8.064 -8.047 -8.038 1999 -8.060 -8.066 -8.147 -8.170 -8.171 -8.138 -8.064 -7.949 -7.825 -7.860 -7.935 -8.008 -8.033 -8.041 2000 -8.077 -8.070 -8.129 -8.200 -8.164 -8.141 -8.065 -7.979 -7.894 -7.918 -7.962 -8.033 -8.053 -8.049 2001 -8.052 -8.089 -8.150 -8.218 -8.219 -8.169 -8.051 -7.964 -7.902 -7.916 -7.988 -8.073 -8.066 -8.064 2002 -8.062 -8.086 -8.162 -8.177 -8.216 -8.203 -8.092 -7.982 -7.912 -7.946 -8.016 -8.075 -8.077 -8.081 Monthly averages have been adjusted to the 15th of each month. Missing values are denoted by 99.999. Annual average data have been augmented (data in parentheses) when only 1 or 2 months are missing for that year, by substituting the monthly fit value(s) for missing (99.999) data and then averaging the 12 values. The month without data is still shown as 99.999 while this recomputed annual average is shown in parentheses. These monthly data have been adjusted from January 1992 to the present by adding -0.112 per mil.