The ACF (Atmospheric Chemistry Format) data format has been created for use on the PMEL Atmospheric Chemistry data server. Each *.acf file is an ASCII file containing a metadata prefix followed by the data. The prefix consists of the following lines:
All *.acf data lines have the following structure.
Time is defined by YEAR, MONTH, DAY of month, HOUR, MINUTE and SECOND. The SECOND column is optional but the data must fit what is defined in the above "#TIME PARAMETERS#". Most data files written before 2003 do not include the SECOND column. The time defined is for the start of the averaging period. The next column is the DURATION in minutes of the averaging period. The next column is the decimal day-of-year (DOY) for the center of the averaging period (noon on Feb. 1 is DOY 32.5). All date/times are in UTC. The next two columns are the latitude and longitude in decimal degrees. South latitudes are always negative. Longitudes can be in one of two conventions, 90 W can be given as -90.0 or as +270.0 (A negative longitude can be added to 360 to give a positive east longitude.) Data parameters follow after the time and position.