******************************************************************** *** Atmospheric CO2-curve values (ppmv) derived from flask air *** *** samples collected at Barrow, Alaska, USA *** *** *** *** Source: R. F. Keeling, S. C. Piper, A. F. Bollenbacher *** *** and S. J. Walker *** *** Carbon Dioxide Research Group *** *** Scripps Institution of Oceanography (SIO) *** *** University of California *** *** La Jolla, California USA 92093-0444 *** *** *** *** May 2008 *** ******************************************************************** Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann. Ave. 1974 336.84 337.11 337.03 337.35 335.44 328.69 322.87 324.36 329.02 332.78 335.30 1975 336.64 337.27 337.55 337.49 337.83 335.93 329.18 323.36 324.90 329.63 333.46 336.03 333.27 1976 337.42 338.09 338.42 338.39 338.76 336.78 329.96 324.20 325.82 330.56 334.40 336.97 334.15 1977 338.38 339.06 339.40 339.40 339.81 337.95 331.18 325.35 326.98 331.84 335.79 338.46 335.30 1978 339.93 340.67 341.05 341.07 341.50 339.64 332.83 326.95 328.58 333.46 337.41 340.07 336.93 1979 341.53 342.25 342.61 342.62 343.03 341.14 334.26 328.33 329.96 334.87 338.86 341.56 338.42 1980 341.68 343.32 344.25 344.31 343.99 342.74 336.84 331.75 332.28 337.66 341.60 344.73 340.43 1981 343.07 343.83 344.25 344.31 344.78 342.84 335.92 330.08 331.80 336.71 340.66 343.30 340.13 1982 345.84 346.56 346.92 346.90 347.28 345.31 338.24 332.15 333.75 338.70 342.72 345.43 342.48 1983 346.93 347.70 348.11 348.18 348.67 346.82 339.85 333.85 335.60 340.68 344.80 347.58 344.06 1984 349.10 349.83 350.18 350.15 350.53 348.43 341.23 335.15 336.85 341.83 345.86 348.59 345.64 1985 350.09 350.84 351.23 351.28 351.74 349.82 342.72 336.59 338.29 343.38 347.50 350.28 346.98 1986 351.81 352.58 352.97 352.99 353.43 351.47 344.29 338.09 339.78 344.88 349.00 351.77 348.59 1987 353.27 354.00 354.36 354.36 354.80 352.82 345.62 339.44 341.21 346.42 350.69 353.62 350.05 1988 355.30 356.22 356.76 356.94 357.55 355.66 348.53 342.56 344.53 349.85 354.16 357.09 352.93 1989 358.71 359.53 359.93 359.95 360.38 358.36 351.02 344.68 346.37 351.54 355.71 358.51 355.39 1990 360.01 360.72 361.05 360.99 361.37 359.28 351.87 345.48 347.18 352.38 356.59 359.42 356.36 1991 360.96 361.70 362.06 362.03 362.44 360.37 352.94 346.52 348.23 353.44 357.63 360.43 357.40 1992 361.90 362.57 362.85 362.74 363.07 360.80 353.20 346.77 348.48 353.66 357.83 360.61 357.87 1993 362.10 362.78 363.09 363.00 363.36 361.22 353.67 347.16 348.89 354.19 358.50 361.40 358.28 1994 363.00 363.80 364.21 364.24 364.71 362.68 355.20 348.78 350.64 356.09 360.53 363.54 359.79 1995 365.23 366.10 366.55 366.61 367.11 365.08 357.55 351.08 352.92 358.36 362.78 365.77 362.10 1996 367.43 368.27 368.71 368.77 369.25 367.09 359.44 352.97 354.82 360.18 364.48 367.36 364.06 1997 368.89 369.60 369.91 369.84 370.23 368.06 360.36 353.73 355.53 360.99 365.44 368.45 365.09 1998 370.15 371.03 371.53 371.65 372.25 370.29 362.75 356.29 358.29 363.92 368.51 371.61 367.36 1999 373.33 374.18 374.60 374.61 375.05 372.89 365.10 358.37 360.16 365.62 370.04 373.00 369.75 2000 374.61 375.37 375.73 375.69 376.11 373.83 365.96 359.31 361.21 366.71 371.16 374.17 370.82 2001 375.82 376.64 377.06 377.09 377.58 375.46 367.65 360.93 362.82 368.43 372.98 376.05 372.38 2002 377.76 378.61 379.06 379.13 379.66 377.57 369.78 363.08 365.05 370.75 375.40 378.55 374.53 2003 380.32 381.23 381.72 381.80 382.33 380.20 372.31 365.51 367.39 373.02 377.55 380.58 377.00 2004 382.20 382.96 383.31 383.25 383.67 381.34 373.32 366.57 368.57 374.28 378.91 382.07 378.37 2005 383.84 384.75 385.23 385.32 385.87 383.75 375.83 369.02 371.00 376.79 381.50 384.70 380.63 2006 386.50 387.42 387.92 388.01 388.57 386.43 378.44 371.56 373.51 379.27 383.92 387.05 383.22 2007 388.75 389.57 389.96 389.95 390.43 388.22 380.15 373.23 375.23 381.08 385.86 389.11 385.13 Values above are taken from a curve consisting of 4 harmonics plus a stiff spline and a linear gain factor, fit to monthly concentration values adjusted to represent 2400 hours on the 15th day of each month. Data used to derive this curve are shown in the accompanying graph. Units are parts per million by volume (ppmv) expressed in the 2003A SIO manometric mole fraction scale. The "annual average" is the arithmetic mean of the twelve monthly values.