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*** Atmospheric CO2 concentrations (ppmv) derived from flask air   ***
*** samples collected at Manua Loa, Hawaii, USA                    ***
*** Source: L.P. Steele                                            ***
***              P.B. Krummel                                      ***  
***              R. L. Langenfelds,                                ***
***              Atmospheric, Research, Commonwealth Scientific,   ***
***              And Industrial Research Organisation,             ***
***              Aspendale, Victoria,                              *** 
***              Australia  3195                                   ***                   
***                                                                ***   
*** August 2007                                                    ***
***                                                                ***
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Month	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Ann. Ave
1991						357.83	355.96	353.61	351.84	352.34	354.13	355.52	
1992	356.56	357.45	358.65	359.26	359.58	358.97	356.59	354.73	353.80	353.75	354.58	355.93	356.65
1993	357.26	357.99	358.55	359.20	359.76	359.43	357.69	354.90	353.19	353.78	355.35	356.83	356.99
1994	357.57	357.89	359.10	360.82	361.38	360.67	359.49	357.64	355.36	355.01	356.76	358.47	358.35
1995	359.67	361.00	362.14	362.87	363.99	363.00	360.31	360.31	360.09	358.65	359.32	360.50	360.99
1996	361.32	362.51	363.55	364.26	364.91	364.59	362.62	360.63	359.39	359.16	360.51	362.24	362.14
1997	362.96	363.26	364.73	366.49	366.67	365.39	363.83	362.11	360.27	360.56	362.72	364.18	363.60
1998	364.84	365.81	367.48	369.13	369.54	368.30	366.81	365.36	363.68	363.89	365.67	367.03	366.46
1999	367.85	368.43	369.55	370.65	370.31	369.61	368.67	366.57	364.81	365.03	366.56	367.87	367.99
2000	369.10	370.28	371.17	371.57	371.62	371.34	369.90	367.99	366.63	366.92	368.38	369.38	369.52
2001	370.39	371.56	372.72	373.88	374.18	373.14	371.07	369.04	367.79	368.20	370.09	371.41	371.12
2002	371.74	372.36	373.44	374.69	375.66	375.28	373.44	371.17	370.16	371.14	372.48	373.80	372.95
2003	374.97	375.77	376.83	378.13	378.89	378.05	376.40	374.58	373.04	373.10	374.58	375.88	375.85
2004	376.46	377.25	378.94	380.53	380.71	379.61	377.50	375.41	374.05	374.32	376.16	377.58	377.38
2005	378.51	379.32	380.42	382.15	382.75	381.99	380.63	378.01	376.10	376.76	378.24	379.68	379.55
2006	380.98	381.83	382.76	384.29	385.20	384.05	382.02	380.17	378.84	378.79	380.16	381.80	381.74

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). Calibration 
details are discussed by Francey et al. (2003).  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.