******************************************************************* *** Atmospheric CO2 concentrations (ppmv) derived from flask *** *** air samples collected at Samoa *** *** *** *** 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 1981 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 -99.99 339.01 339.04 339.68 339.90 -99.99 -99.99 1982 340.67 340.96 340.21 340.76 339.83 340.21 341.12 341.34 340.52 340.10 340.55 340.91 340.60 340.58 1983 340.60 341.01 341.01 341.83 341.98 342.40 342.37 342.39 342.16 342.63 342.94 342.58 341.99 342.11 1984 343.83 343.92 344.01 343.55 342.91 343.07 343.46 343.83 344.52 344.21 344.01 344.78 343.84 343.83 1985 344.93 345.30 345.41 345.48 344.16 344.97 344.81 345.24 346.29 345.42 345.38 -99.99 (345.28) 345.28 1986 346.34 -99.99 346.52 346.86 344.71 346.33 345.99 345.87 -99.99 347.23 347.10 346.94 (346.38) 346.37 1987 347.12 347.69 348.71 347.16 347.37 347.40 347.67 348.12 348.30 348.33 349.00 349.36 348.02 347.97 1988 349.70 350.03 349.50 349.80 349.59 349.72 349.98 350.18 350.09 350.44 350.85 351.30 350.10 350.11 1989 351.71 352.06 351.13 351.94 351.95 351.17 351.31 351.37 351.39 351.47 351.95 351.90 351.61 351.59 1990 352.35 351.72 352.92 353.15 352.44 353.11 352.93 353.20 353.30 352.75 353.42 353.79 352.92 353.02 1991 354.59 355.00 354.76 354.01 353.93 354.18 354.36 354.21 353.91 353.87 354.70 355.00 354.38 354.28 1992 354.07 354.93 354.92 354.80 355.05 355.33 355.69 355.65 355.23 355.60 355.22 355.89 355.20 355.23 1993 355.39 355.85 356.38 355.70 354.97 356.03 356.10 356.41 356.07 356.42 356.66 356.96 356.08 356.11 1994 357.34 357.85 357.33 357.33 357.23 357.76 357.47 357.55 357.81 357.84 358.46 358.94 357.74 357.74 1995 358.58 359.71 359.31 358.83 359.76 359.44 360.12 359.72 359.52 359.80 360.29 360.76 359.65 359.69 1996 361.56 362.01 362.05 360.24 360.91 361.33 360.96 361.44 360.97 361.05 361.61 362.04 361.35 361.23 1997 362.43 362.16 361.52 362.42 361.27 361.56 362.21 362.07 362.34 362.98 363.24 363.47 362.31 362.28 1998 363.85 363.56 363.64 363.34 364.09 364.82 364.99 365.22 365.38 365.61 366.11 366.30 364.74 364.79 1999 366.86 366.70 366.34 367.04 366.56 366.74 367.44 367.20 366.93 366.93 367.24 367.61 366.97 366.99 2000 368.39 368.55 368.00 367.83 367.15 367.11 368.42 368.31 368.10 368.63 368.88 368.95 368.19 368.21 2001 369.55 370.07 370.08 369.77 368.94 369.58 370.33 370.05 369.79 370.07 370.45 370.74 369.95 369.91 2002 370.99 371.77 371.92 371.04 370.76 371.65 371.99 371.96 372.05 372.60 373.18 373.42 371.94 371.94 2003 373.41 373.00 374.69 374.17 373.97 373.28 374.32 374.67 374.18 374.16 374.64 375.18 374.14 374.20 2004 375.45 376.48 375.87 375.26 375.02 375.98 375.58 376.34 375.98 376.06 376.18 377.06 375.94 375.89 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.