******************************************************************* *** Atmospheric CO2 concentrations (ppmv) derived from flask *** *** air samples collected at Point Barrow, Alaska *** *** *** *** 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 1974 336.18 -99.99 337.11 336.39 337.01 336.42 330.83 323.07 323.95 327.80 332.56 335.11 (332.77) 332.77 1975 337.12 338.72 336.60 337.36 337.41 335.54 329.99 324.21 324.92 329.26 333.61 335.61 333.36 333.28 1976 337.07 337.33 338.42 339.41 338.65 336.65 330.93 324.41 326.36 329.64 333.52 337.67 334.17 334.15 1977 338.08 337.27 337.93 -99.99 340.35 338.04 -99.99 326.16 326.73 331.11 334.95 339.58 (335.08) 335.31 1978 339.21 340.65 342.77 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 339.45 339.29 -99.99 336.99 1979 340.58 341.56 343.30 342.53 343.43 342.94 335.14 -99.99 329.12 333.64 337.55 342.17 (338.36) 338.42 1980 341.68 343.32 344.28 -99.99 343.99 342.75 336.84 331.75 332.28 337.64 341.59 344.73 (340.43) 340.15 1981 344.80 344.40 344.60 346.12 346.20 343.87 335.45 330.24 333.25 338.26 341.29 344.01 341.04 341.39 1982 344.47 347.85 347.51 347.45 347.48 345.85 339.36 331.89 332.79 338.46 342.64 344.99 342.56 342.51 1983 346.78 346.80 347.73 347.93 348.16 348.22 340.25 331.93 335.71 341.17 345.80 346.34 343.90 344.07 1984 349.40 350.99 350.34 349.79 350.87 348.94 341.12 335.60 337.21 341.43 344.66 348.08 345.70 345.65 1985 349.64 349.28 350.74 351.27 352.67 349.99 343.97 337.40 338.31 343.65 347.37 348.68 346.91 346.98 1986 349.70 352.41 354.23 353.38 354.01 351.11 344.85 337.51 340.90 346.11 348.30 351.58 348.67 348.60 1987 353.16 353.42 354.66 354.08 355.06 353.70 346.61 339.54 340.87 345.67 349.49 352.69 349.91 350.05 1988 355.30 357.00 356.45 357.83 356.76 355.18 348.08 342.61 345.61 350.29 354.98 358.09 353.18 352.94 1989 359.86 359.26 359.96 359.85 359.52 360.18 352.25 342.02 344.95 350.67 355.96 358.62 355.26 355.34 1990 359.46 360.97 361.77 361.57 362.21 356.86 351.31 344.18 346.30 352.72 356.47 358.34 356.01 356.26 1991 361.42 361.02 362.47 361.91 362.18 360.16 352.94 346.86 347.77 353.61 358.90 360.32 357.47 357.38 1992 362.05 362.34 362.37 363.03 362.48 361.06 354.31 347.22 347.59 353.31 356.71 360.91 357.78 357.88 1993 362.83 362.29 363.62 363.39 363.78 360.79 352.07 347.32 348.52 354.19 358.35 361.49 358.22 358.28 1994 362.20 364.38 365.25 364.56 364.55 363.18 354.37 347.73 350.01 356.10 359.35 364.74 359.70 359.78 1995 365.44 366.91 366.76 367.23 366.23 364.63 357.67 350.79 353.51 357.44 -99.99 365.35 (362.05) 362.09 1996 367.07 -99.99 368.00 368.11 369.87 367.72 360.89 353.11 355.11 362.08 363.36 366.89 (364.20) 364.07 1997 370.27 369.42 368.46 370.43 369.76 368.80 360.06 352.30 355.92 361.10 366.39 367.38 365.02 365.06 1998 369.86 372.37 370.86 371.20 371.70 370.62 360.30 356.32 -99.99 364.72 368.80 373.12 (367.34) 367.36 1999 374.14 374.77 374.01 374.55 375.38 373.17 363.28 358.65 360.18 364.63 -99.99 372.96 (369.64) 369.76 2000 374.52 376.46 374.76 375.67 376.70 373.36 365.49 360.00 361.88 366.80 370.57 373.54 370.81 370.82 2001 375.29 376.70 376.81 377.67 377.55 375.45 368.00 360.81 363.40 369.00 372.52 376.46 372.47 372.38 2002 378.37 377.82 379.13 379.10 379.18 376.48 370.87 362.76 365.89 370.70 375.62 377.20 374.43 374.51 2003 379.00 382.27 381.44 381.43 382.21 380.76 371.00 364.74 368.28 372.46 378.59 382.53 377.06 376.93 2004 382.59 383.21 382.17 383.80 383.47 380.50 371.75 366.50 367.86 373.46 379.19 382.31 378.07 378.36 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.