********************************************************************** *** Atmospheric CO2 concentrations (ppmv) derived from flask air *** *** samples collected at Alert, NWT, Canada *** *** Source: L.P. Steele *** *** P.B. Krummel *** *** R. L. Langenfelds, *** *** Atmospheric, Research, Commonwealth Scientific, *** *** And Industrial Research Organisation, *** *** Aspendale, Victoria, *** *** Australia 3195 *** *** *** *** August 2007 *** *** *** ********************************************************************** Month Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Ann. Ave 1991 353.83 348.04 348.69 353.07 357.65 362.49 1992 363.73 361.90 362.14 363.06 363.00 360.86 354.03 347.50 347.62 351.68 356.60 360.53 357.72 1993 361.99 362.34 362.95 363.74 363.77 361.16 354.93 349.12 350.33 355.29 357.56 359.63 358.57 1994 361.81 362.86 364.03 364.58 364.39 362.27 356.05 351.10 352.99 356.66 359.91 363.55 360.02 1995 365.78 366.09 365.49 365.42 365.72 363.53 357.25 352.44 353.38 357.85 362.39 364.87 361.68 1996 366.21 367.36 367.59 367.74 368.56 366.93 361.26 355.51 354.89 359.32 363.78 365.97 363.76 1997 367.39 368.23 368.48 368.85 369.00 367.30 361.19 354.93 355.69 360.49 364.55 367.44 364.46 1998 369.75 370.77 370.46 370.42 371.13 369.43 363.32 358.21 359.15 363.82 368.41 371.03 367.16 1999 372.21 373.19 373.84 374.17 374.33 371.95 364.94 359.14 359.93 364.33 369.09 372.11 369.10 2000 373.51 374.61 375.07 375.21 375.61 373.43 367.15 361.57 361.80 366.14 370.45 372.96 370.63 2001 374.30 375.40 376.25 377.24 377.53 373.86 367.21 362.50 362.78 368.11 373.52 375.38 372.01 2002 376.31 377.57 378.50 378.61 378.45 376.56 370.44 364.66 365.42 369.49 373.94 378.55 374.04 2003 380.54 380.16 380.09 380.95 381.96 379.61 372.71 367.54 368.53 372.89 377.35 380.56 376.91 2004 382.02 381.93 382.52 383.72 383.82 381.54 375.10 368.80 368.68 373.37 377.90 381.39 378.40 2005 384.06 384.44 384.30 384.92 385.32 383.20 376.57 370.98 371.60 376.07 381.88 385.48 380.74 2006 385.20 385.10 386.45 387.46 388.51 386.86 379.68 373.54 374.53 379.08 383.49 386.69 383.05 1996 366.21 367.36 367.59 367.74 368.56 366.93 361.26 355.51 354.89 359.32 363.78 365.97 363.76 1997 367.39 368.23 368.48 368.85 369.00 367.30 361.19 354.93 355.69 360.49 364.55 367.44 364.46 1998 369.75 370.77 370.46 370.42 371.13 369.43 363.32 358.21 359.15 363.82 368.41 371.03 367.16 1999 372.21 373.19 373.84 374.17 374.33 371.95 364.94 359.14 359.93 364.33 369.09 372.11 369.10 2000 373.51 374.61 375.07 375.21 375.61 373.43 367.15 361.57 361.80 366.14 370.45 372.96 370.63 2001 374.30 375.40 376.25 377.24 377.53 373.86 367.21 362.50 362.78 368.11 373.52 375.38 372.01 2002 376.31 377.57 378.50 378.61 378.45 376.56 370.44 364.66 365.42 369.49 373.94 378.55 374.04 2003 380.54 380.16 380.09 380.95 381.96 379.61 372.71 367.54 368.53 372.89 377.35 380.56 376.91 2004 382.02 381.93 382.52 383.72 383.82 381.54 375.10 368.80 368.68 373.37 377.90 381.39 378.40 2005 384.06 384.44 384.30 384.92 385.32 383.20 376.57 370.98 371.60 376.07 381.88 385.48 380.74 2006 385.20 385.10 386.45 387.46 388.51 386.86 379.68 373.54 374.53 379.08 383.49 386.69 383.05 Monthly values are expressed in parts per million (ppm) and reported in the WMO CO2 Mole Fraction Scale (Zhao et al., 1997, J. Geophys. Res. 102 , 5885-5894). Monthly values are calculated as the mean of the daily values from a smooth curve fit to the data using curve-fitting routines described by Thoning et. al., 1989, (J. Geophys. Res. 94, 8549-8565). Annual values are the arithmetic means of the 12 monthly values.