******************************************************************* *** Atmospheric CO2 concentrations (ppmv) derived from flask *** *** and in situ air samples collected at Christmas Island *** *** (flask data, 1972-1976 Fanning Island, 1977-1983 both) *** *** Source: C.D. Keeling *** *** T.P. Whorf, and the Carbon Dioxide Research Group *** *** Scripps Institution of Oceanography (SIO) *** *** University of California *** *** La Jolla, California USA 92093-0444 *** *** *** *** May 2005 *** *** *** ******************************************************************* Year Jan. Feb. Mar. Apr. May Jun. July Aug. Sept. Oct. Nov. Dec. Annual Annual-Fitted 1972 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 328.11 327.22 327.99 326.95 326.77 328.66 -99.99 -99.99 1973 328.74 329.70 330.66 331.93 331.58 330.19 330.13 330.46 -99.99 -99.99 329.08 329.46 (329.99) 329.96 1974 330.33 330.60 331.16 332.77 330.57 330.51 330.29 329.99 329.31 329.32 330.17 330.19 330.44 330.54 1975 331.52 -99.99 -99.99 333.25 333.39 332.31 331.29 331.35 330.98 330.26 330.67 331.65 (331.72) 331.60 1976 332.26 331.68 333.62 333.62 333.70 332.98 333.29 332.18 331.21 331.42 -99.99 332.04 (332.48) 332.58 1977 333.09 333.95 335.04 336.01 335.54 335.20 334.53 333.91 333.62 333.18 333.46 333.89 334.29 334.26 1978 335.11 335.81 335.95 336.64 336.68 336.05 336.02 335.80 335.11 335.14 334.75 335.50 335.71 335.68 1979 336.18 337.01 337.32 338.38 338.97 337.87 337.57 336.88 336.35 336.30 336.77 337.39 337.25 337.33 1980 -99.99 338.64 339.95 340.43 339.87 339.58 340.07 339.22 338.45 338.09 338.70 339.02 (339.19) 339.17 1981 340.60 340.42 341.37 341.21 340.96 -99.99 340.68 339.68 339.18 339.09 339.65 340.52 (340.35) 340.32 1982 -99.99 341.78 342.11 342.96 342.19 -99.99 -99.99 -99.99 340.42 -99.99 -99.99 341.12 -99.99 341.43 1983 341.63 342.93 343.28 345.19 345.04 -99.99 -99.99 343.34 -99.99 -99.99 342.25 342.67 -99.99 343.33 1984 343.71 344.28 345.83 346.82 346.06 345.64 344.94 344.45 343.38 343.06 343.90 344.67 344.73 344.73 1985 345.35 345.48 346.69 347.53 347.10 347.00 346.37 345.60 344.79 344.73 344.96 345.93 345.96 345.94 1986 346.47 346.54 347.62 348.64 347.93 347.91 347.59 347.13 346.72 346.36 346.47 346.77 347.18 347.18 1987 347.59 348.17 349.09 349.55 350.36 349.36 349.55 349.31 348.56 348.63 348.54 349.75 349.04 349.07 1988 350.58 351.25 351.92 353.16 352.31 351.86 351.54 350.34 350.53 350.76 351.14 351.68 351.42 351.46 1989 352.46 353.02 354.04 354.09 353.70 353.66 352.79 352.80 352.18 352.02 352.06 352.60 352.95 352.95 1990 353.74 354.60 355.11 354.80 354.46 -99.99 -99.99 -99.99 -99.99 353.36 353.68 -99.99 -99.99 354.13 1991 355.17 355.60 355.68 356.39 -99.99 356.33 355.58 354.47 354.20 354.60 354.64 355.06 (355.34) 355.32 1992 355.76 357.14 356.85 -99.99 357.83 357.53 -99.99 356.07 354.89 355.36 355.21 356.29 (356.45) 356.33 1993 356.91 356.95 357.37 359.17 358.47 357.99 357.91 357.48 356.62 355.90 -99.99 357.99 (357.45) 357.41 1994 358.21 358.51 359.33 360.44 359.91 359.46 359.43 359.86 358.39 358.75 -99.99 -99.99 (359.19) 359.15 1995 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 361.25 360.61 360.40 360.62 -99.99 361.41 -99.99 361.13 1996 362.35 363.21 364.16 -99.99 -99.99 363.68 363.48 362.53 -99.99 -99.99 -99.99 -99.99 -99.99 363.09 1997 363.57 364.00 364.79 365.02 -99.99 364.03 364.64 -99.99 362.88 362.70 362.30 364.67 (363.94) 364.15 1998 -99.99 -99.99 368.40 368.82 -99.99 367.17 366.87 366.29 366.14 366.50 366.35 367.35 -99.99 366.72 1999 -99.99 368.97 369.84 370.27 368.55 369.08 368.82 367.81 367.79 367.25 368.20 368.79 (368.61) 368.54 2000 369.61 369.88 370.42 371.92 370.60 370.40 371.32 369.58 368.86 369.28 369.27 -99.99 (370.09) 370.03 2001 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 371.02 -99.99 -99.99 -99.99 -99.99 -99.99 371.49 2002 -99.99 -99.99 -99.99 -99.99 374.66 374.05 -99.99 -99.99 -99.99 373.27 373.59 374.24 -99.99 373.77 2003 -99.99 375.35 376.09 -99.99 -99.99 -99.99 377.91 376.13 375.07 374.67 375.57 376.74 377.80 375.98 2004 377.05 376.70 378.54 379.51 379.80 377.42 -99.99 377.14 377.18 377.77 376.62 377.95 -99.99 377.83 Monthly values are expressed in parts per million (ppm) and reported in the 2003A SIO manometric mole fraction scale. The monthly values have been adjusted to the 15th of each month. Missing values are denoted by -99.99. The "annual" average is the arithmetic mean of the twelve monthly values. In years with one or two missing monthly values, annual values were calculated by substituting a fit value (4-harmonics with gain factor and spline) for that month and then averaging the twelve monthly values.