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Contents of the "ale_gage_agage" data directory

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There are four subdirectories in this area:
(1) "ale"  , presenting data (1978-1986) from the Atmospheric Lifetime Experiment;
(2) "gage" , presenting data (1982-1996) from the Global Atmospheric Gases Experiment
(3) "agage", presenting data (1993-current) from the Advanced Global Atmospheric Gases Experiment.
(4) "global_mean", for monthly global means from AGAGE measurements

The subdirectories, "ale" and "gage", each contain two additional subdirectories:
(1) "complete", presenting data for all individual measurements (generally made 
4 times daily at each site for ALE, 12 times daily at each site for GAGE) 
(2) "monthly", presenting monthly summary averages of the individual measurements.
Please note that for the "ale" and "gage" data sets all of the time values are 
quoted in terms the local standard time appropriate to the individual station. 
For the "agage" data, however, all time values are in universal (UTC, formerly GMT)
time. 

The subdirectory "agage" is further divided into three subdirectories, "gc-md",
"gc-ms", and "gc-ms-medusa" to group data measured by different instruments.
Data in those areas are further divided into three sub-directories, (1) "complete" 
and (2) "monthly", are used for individual (high frequency) measurements and monthly
averages, respectively, as those descibed in "ale" and "gage" data section. The 
third subdirectory, (3) "precisions", is used for daily standard deviations of 
instrument precision data for each compound at each station.