**********************************************************************
*** Atmospheric H2 concentrations (ppbv) derived from flask       ***
*** samples collected at  Mawson, Antarctica                       ***
*** Source: L.P. Steele                                            ***
***              P.B. Krummel                                      ***  
***              R.L. Langenfelds                                  ***
***              Commonwealth Scientific,                          ***
***              and Industrial Research Organisation,             ***
***              Aspendale, Victoria,                              *** 
***              Australia  3195                                   ***                   
***                                                                ***   
*** March 2003                                                     ***
***                                                                ***
**********************************************************************

Year	Jan.	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Ann. Ave.

1992		527.12	526.83	525.21	521.9	518.26	514.31	511.94	512.83	514.66	518	521.33	
1993	522.58	523.76	524.14	522.34	517.92	513.09	510.06	507.67	508.24	512.52	517.16	521.9	516.78
1994	525.35	525.16	523.73	521.18	516.84	513.86	512.24	510.97	513.44	519.23	524.1	529.13	519.60
1995	534.04	535.34	532.84	530.43	528.93	524.81	520.83	518.46	518.55	523.4	529.87	535.82	527.78
1996	538.53	537.43	535.74	533.25	528.71	525.18	522.39	519.31	519.12	522.25	526.69	531.3	528.33
1997	535.99	537.07	533.68	530.15	528.01	524.98	520.84	518.48	520.7	525.4	529.17	533.32	528.15
1998	538.07	540.77	540.48	537.49	534.35	531.7	529.33	528.43	529	531.84	536.34	540.19	534.83
1999	543.92	544.96	543.16	540.01	535.33	531.76	528.27	524.85	525.71	530.27	535.71	541.31	535.44
2000	545.83	545.65	543.18	540.72	535.56	530.54	527.2	524.51	524.2	524.96	528.17	532.26	533.57
2001	534.26	535.28	535.38	533.76	529.56	524.58	521.52	520.17	520.56	523.07	526.01	530.07	527.85

Monthly values are expressed in parts per billion per volume (ppbv) and reported in the CSIRO94 H2 scale. 
Monthly values were calculated as the mean of the daily values from a smooth curve fit to the data using 
the 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.