Notes: (The lastest  update in May 2006)

     1. All ALE data (except N2O) have been calibrated to the Scripps
        Institution of Oceanography's SIO-2005 scale. The factors
        (SIO-2005/SIO-1998) for measured species are following,

        Species   factor (SIO-2005/SIO-1998)
       ========   ==========================
        CFC-11,     0.9945
        CFC-12,     1.000
        CH3CCl3,    0.9957
        CCl4,       1.000

     2. The N2O data are still in SIO-1998 scale


---------------------------------------------------------------------
Notes: (previous update in July 2000)

     1. ALE data has been calibrated to the SIO-1998 scale. Please see
        Prinn et al., (2000) paper for detail description of SIO-1998
        scale.

     2. All times during the ALE program are in local standard time.

     3. N2O data at Samoa from the station start-up in July, 1978
        to November 10, 1978 have been removed from the data base
        as being unreliable due to an incorrect sample loop size
        that was used during that period. Until now this data has
        been retained in the data base with a warning as to its
        unreliability (see Prinn, et.al, J. Geophys. Res., Vol. 95,
        No. D11, page 18,371, October 20, 1990). (June, 1998)

     4. Two time values at Samoa on May 15, 1986 have been altered
        by a few hours to correct a typographical error found in the
        original data. ((June, 1998)

Reference:

     1. Prinn et al., A history of chemically and radiatively important
        gases in air deduced from ALE/GAGE/AGAGE, J. Geophys. Res., 105,
        No. D14, p17,751-17,792, 2000.