The original lef200305_2.co2 was renamed as lef200305_2_bad.co2.  
It contains no good co2 data.  The original lef200305_1.co2 was 
renamed as lef200305_1.co2 because it contains good data from all
levels beginning around 5/16/03.  Normally, the _1.co2 files 
only contain 396m data.