NOAA KLM User's Guide
The Aerosol Monthly Mean Field File is a gridded file of optical thicknesses and other information. The optical thickness at each gridpoint is the average of the optical thicknesses calculated for each week within the month at that gridpoint. If an analyzed field was updated during the month, then it will be used in the calculation of the monthly mean.
The first record is a header which contains satellite ID, the month, the year, and the number of fields used in the computation of the mean. The remaining records are data records. Each data record contains all data for one latitudinal row. The latitude range is from -70 to 70 degree. The first data record will contain data from the -70 degree latitude row and the second will contain data from the -69 degree row and so on. Each row will begin with information from the -180 degree meridian and progress Eastward to the 179 degrees meridian. Each gridpoint will contain 10 bytes of information thus each record will contain 3600 bytes.
The format of the header record is contained in Table 220.127.116.11-1.
|2||Year||1988 - ?|
|4||Number of fields used in mean calculation||1-5|
Each data record represents one row of latitude with each 5 halfwords representing a specific gridpoint or intersection with a meridian. Table 18.104.22.168-2 shows the format of the grid intersections in the data record.
|1||Average Optical Thickness||0 to2440, -999=land|
|2||Maximum Weekly Optical Thickness for the Month||0 to2440, 0=land|
|3||Minimum Weekly Optical Thickness for the Month||0 to2440, 0=land|
|4||Number of weekly field values which were analyzed from at least 1 retrieval which was less than 8 days old.||0 to 5, 0=land|
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